CN114242583B - Etching method of AlGaN material and application thereof - Google Patents

Abstract

The invention discloses an AlGaN material etching method and application thereof. The etching method of the AlGaN material comprises: placing the AlGaN material in an etching chamber of an etching device; introducing an etching gas comprising HBr, O ₂ and SF ₆ into the etching chamber, and using plasma A power source converts the etching gas into a plasma, which is then brought into contact with selected regions of the surface of the AlGaN material. An AlGaN material etching method provided in an embodiment of the present invention uses a specific ratio of O ₂ and SF ₆ as an auxiliary etching gas to cooperate with the main etching gas, which can not only prevent the formation of etching residues, but also remove the etching residues. Etching residues, forming a flat etching surface, will not affect the etching rate, and, in the etching process, do not use Cl-containing etching gas, so that it will not form difficult-to-remove AlGaCl _x raised residues , thereby improving the quality of etching.

Description

AlGaN Material Etching Method and Its Application

technical field

The invention relates to an etching method of an AlGaN material, in particular to an etching method of an AlGaN material and an application thereof, belonging to the technical field of semiconductors.

Background technique

As the materials of GaN system are getting more and more attention, the light-emitting devices and power devices of GaN system have also received extensive attention from scientific research institutions and enterprises. In the structures of lasers, LEDs, HEMTs, mini LEDs and micro LEDs embodied in GaN All will use AlGaN materials, and the layer structure of the device will be etched in the device formation process. The inductively coupled plasma (ICP) dry etching process is a common etching process, and the etching of AlGaN materials is usually used Chlorine-containing gas is used for etching, and chlorine-containing gas is usually selected such as chlorine gas, boron trichloride, etc., and when the chlorine-containing gas etches AlGaN, a small amount of chlorine ions will react with AlGaN to form AlGaClx substances, which are etched It is difficult to remove when it is difficult to remove, and some cross-shaped raised structures will be formed. As shown in Figure 1, the uneven raised structures formed have a great influence on the flatness of the etched surface, because the uneven surface will affect other layers of the device. The formation and migration of device carriers have a great impact, which will directly have a serious impact on device performance. Therefore, it is still an urgent technical problem to be solved in the industry to provide an etching method that replaces chloride ions and realizes fast etching of AlGaN materials to form a flat surface.

Contents of the invention

The main purpose of the present invention is to provide an AlGaN material etching method and its application, so as to overcome the deficiencies in the prior art.

In order to realize the aforementioned object of the invention, the technical solutions adopted in the present invention include:

An embodiment of the present invention provides an etching method for an AlGaN material, comprising: converting an etching gas containing HBr, O ₂ and SF ₆ into plasma, and making the plasma contact the AlGaN material.

An embodiment of the present invention provides an etching method for an AlGaN material, including:

placing the AlGaN material in an etching chamber of an etching device;

Into the etching chamber, the etching gas containing HBr, O ₂ and SF ₆ is introduced, and the etching gas is converted into plasma with a plasma power source, and then the plasma is combined with the surface of the AlGaN material Selected area contacts.

An embodiment of the present invention provides a method for manufacturing an AlGaN device, including the step of performing dry etching on the AlGaN layer in the AlGaN device by using the AlGaN material etching method.

Compared with the prior art, the AlGaN material etching method _provided by the embodiment of the present invention can _not only prevent etching Formation of residues and removal of etching residues to form a flat etching surface without affecting the etching rate, and, in the etching process, no etching gas containing Cl is used, so that no formation of difficult-to-remove AlGaCl _x raised residues, thereby improving the quality of etching.

Description of drawings

FIG. 1 is an SEM image of an AlGaN material etched with a chlorine-containing gas in the prior art;

2 is a schematic flow diagram of an etching method for an AlGaN material provided in a typical implementation case of the present invention;

FIG. 3 is an SEM image of AlGaN material after etching in Embodiment 6 of the invention.

Detailed ways

In view of the deficiencies in the prior art, the inventor of this case was able to propose the technical solution of the present invention after long-term research and extensive practice. The technical solution, its implementation process and principle will be further explained as follows.

An embodiment of the present invention provides an etching method for an AlGaN material, comprising: converting an etching gas containing HBr, O ₂ and SF ₆ into plasma, and making the plasma contact the AlGaN material.

In some more specific embodiments, O ₂ and SF ₆ are mixed in advance to form a mixed gas, and then the mixed gas and HBr gas are used as the etching gas.

In some more specific embodiments, the molar ratio of _O2 and _SF6 in the mixed gas is (1.5-2): 1, and the molar ratio of the HBr gas to the mixed gas formed by _O2 and _SF6 is (6-25): (1-4).

In some more specific embodiments, the AlGaN material etching method includes: using a plasma power source with a power of 500-800W to convert the etching gas into plasma.

An embodiment of the present invention provides an etching method for an AlGaN material, including:

placing the AlGaN material in an etching chamber of an etching device;

Into the etching chamber, the etching gas containing HBr, O ₂ and SF ₆ is introduced, and the etching gas is converted into plasma with a plasma power source, and then the plasma is combined with the surface of the AlGaN material Selected area contacts.

In some more specific embodiments, the AlGaN material etching method specifically includes: first mixing O ₂ and SF ₆ to form a mixed gas, and then passing the mixed gas formed by the O ₂ and SF ₆ and HBr gas into the etching chamber.

In some more specific embodiments, the etching method of the AlGaN material specifically includes:

Introduce the etching gas into the etching chamber, control the flow rate of HBr gas to 80-200 sccm, the flow rate of the mixed gas formed by _O2 and _SF6 to be 10-40 sccm, and the flow rate of the carrier gas to be 80-200 sccm. 400 sccm,

And, control the pressure in the etching chamber to be 20-80mtorr, convert the etching gas into plasma with a plasma power source with a power of 500-800W, and apply 200-300V to the AlGaN material bias voltage and bring the plasma into contact with selected regions of the surface of the AlGaN material.

In some more specific embodiments, in the mixed gas, the molar ratio of _O2 and _SF6 is (1.5-2):1, and the molar ratio of the HBr gas to the mixed gas formed by _O2 and _SF6 For (6-25): (1-4).

In some more specific embodiments, the etching method of the AlGaN material also includes: placing the AlGaN material in the etching chamber of the etching equipment, and raising the temperature in the etching chamber to 500- 600° C., and then use nitrogen to blow the surface of the AlGaN material to complete the surface cleaning treatment of the AlGaN material, and then etch the AlGaN material.

An embodiment of the present invention provides a method for manufacturing an AlGaN device, including the step of performing dry etching on the AlGaN layer in the AlGaN device using the AlGaN material etching method; of course, the AlGaN device The fabrication method also includes the steps of fabricating other structures before and after etching the AlGaN layer, wherein the steps of fabricating other structures depend on different types of specific devices, and are not specifically limited here.

The technical solution, its implementation process and principle will be further explained in conjunction with the accompanying drawings as follows. Unless otherwise specified, the manufacturing processes of the AlGaN layer, the stress buffer layer and other structural layers in the embodiments of the present invention are all in the field. Known by the skilled person, alternatively, a commercially available AlGaN epitaxial wafer can be directly used, and no specific limitation is made here. It should be understood that the embodiment of the present invention mainly explains and illustrates the etching method of the AlGaN material provided by the present invention. The etching equipment and growth equipment used therein are all known to those skilled in the art, and are not specifically limited here.

Please refer to FIG. 2, an etching method for an AlGaN material, which specifically includes the following steps:

1) Provide a substrate and form an AlGaN layer on the substrate;

It should be noted that the substrate can be a sapphire substrate, a silicon carbide substrate or a gallium nitride substrate; in order to improve the crystal quality of the AlGaN layer, when selecting sapphire or silicon carbide as the substrate, the substrate can be A stress buffer layer is formed on the stress buffer layer, and then an AlGaN layer is formed on the stress buffer layer. The material of the stress buffer layer can be aluminum nitride, and when gallium nitride is selected as the substrate, since the AlGaN layer and the gallium nitride substrate The lattice matching of the bottom is better, so there is no need to consider the problem of lattice mismatch, and there is no need to form a stress buffer layer on the gallium nitride substrate;

It should be understood that, depending on the type of device to be fabricated, the position and thickness of the functional layer of the AlGaN layer as a different device, the Al content of the AlGaN layer is also different, and the thickness of the AlGaN layer formed is also different. The present invention mainly studies For the etching process of AlGaN, therefore, there is no specific limitation on the Al content and thickness of the AlGaN layer;

In addition, since the deposition and formation of the AlGaN layer is usually carried out in MOCVD equipment, and the etching is carried out in the ICP equipment, therefore, after the AlGaN layer is deposited and formed, the AlGaN material to be etched needs to be taken out and then transported to the ICP In the equipment, although there are requirements for the transportation environment during the transportation process, the AlGaN layer will inevitably come into contact with the external environment. Therefore, when the AlGaN material is transported to the ICP equipment, the AlGaN layer needs to be cleaned first. The cleaning process Including: first heating the temperature in the etching chamber to 500-600°C, and then using nitrogen to purge the surface of the AlGaN layer. The temperature environment of 500-600°C can remove the water vapor that may be adsorbed on the surface of the AlGaN layer. Remove the impurity substances that may adhere to the surface of the AlGaN layer to prevent the impurities adhered to the surface of the AlGaN layer from being difficult to remove during etching;

Of course, depending on the type of device to be manufactured and the etching target, the AlGaN layer can be etched with different thicknesses and sizes. The etching depth is not required at first, and the AlGaN layer can be etched regionally according to the etching method of the present invention;

2) After performing surface cleaning treatment on the surface of the AlGaN layer or without surface cleaning treatment, use inductively coupled plasma etching (ICP) equipment to etch the AlGaN layer, specifically including:

The AlGaN material is placed in the etching chamber of the inductively coupled plasma etching (ICP) etching equipment, and the HBr gas and the mixed gas formed by mixing _O2 and _SF6 are introduced into the etching chamber together. As etching gas, control the flow rate of HBr wherein to be 80-200sccm, the flow rate of carrier gas to be 80-400sccm, the flow rate of the mixed gas formed by _O2 and _SF6 to be 10-40sccm, wherein, HBr is the main etching gas , O ₂ and SF ₆ are used as auxiliary etching gases, and the carrier gas is an inert gas, such as He gas or Ar gas, etc.,

And, control the pressure in the etching chamber to be 20-80mtorr, convert the etching gas into plasma with a plasma power source with a power of 500-800W, and apply 200-300V to the AlGaN material The bias voltage is applied, and the plasma is brought into contact with a selected area on the surface of the AlGaN material, thereby realizing etching of the AlGaN material.

It should be noted that before entering the etching chamber, O ₂ and SF ₆ are mixed according to the molar ratio (1.5-2): 1 to form a mixed gas, and then the mixed gas of O ₂ and SF ₆ is mixed according to the flow rate 10-40 sccm is passed into the etching chamber, and the molar ratio of the HBr gas to the mixed gas formed by O ₂ and SF ₆ is (6-25):(1-4).

In an etching method for an AlGaN material provided in an embodiment of the present invention, HBr is used as the main etching gas during the etching process. Since the chemical activity of Br radicals is much lower than that of other halogen elements, The electronegativity of halogen elements is: F (3.98) > Cl (3.16) > Br (2.96), the electronegativity of Br ions is low, and it will not react with AlGaN to form AlGaBr during the etching process of AlGaN materials. Substance, and the etching is relatively mild, it will not cause large etching damage to the sidewall of the etched area of AlGaN material or the formed etched structure (such as grooves, etc.), and the surface of the etched area after etching is relatively flat , at the same time, the embodiment of the present invention uses O ₂ and SF ₆ as auxiliary etching gases, and the amount of feed is small; because O ₂ has a strong oxidation performance, the presence of O ₂ can prevent the formation of residues in the etching process and accumulation, as well as, it can also oxidize the damaged area generated during the etching process, and remove the oxidized area by etching with the help of HBr gas, which helps to form a flat shape; while the etching rate of SF ₆ is faster, Thereby, the etching rate can be increased, but if _SF6 is used for etching alone, although the etching rate will be faster due to the highest electronegativity of F, the etching process (such as etching grooves) will be relatively fast. ) causes damage to the bottom and sidewalls, which is not conducive to the formation of flat trench morphology; therefore, in the auxiliary etching gas, the molar amount of O ₂ is more than that of SF ₆ , which can speed up the etching at the same time _Oxygen is used to repair the sidewall of the etching region, which helps to accelerate the etching rate and form a smooth surface. Therefore, in the present invention, the molar ratio of O _{and SF} is controlled at (1.5-2 ):1.

The technical solution, its implementation process and principle will be further explained in conjunction with specific embodiments as follows.

In the following embodiments, the same AlGaN material is dry-etched by selecting different etching gases, and the etching depth and etching morphology of the etching area of each embodiment are observed.

The carrier gas used in the following examples is Ar gas, and the flow rate of the carrier gas is kept consistent, that is, 80-400 sccm, and the etching time in the following examples is controlled to be the same. It should be noted that the following examples use The models and specifications of the inductively coupled plasma etching (ICP) etching equipment are the same, and the same AlGaN material refers to the same manufacturing process and size specifications of the AlGaN material.

Example 1

A kind of etching method of AlGaN material, comprises the steps:

placing the AlGaN material in an etching chamber of an inductively coupled plasma etching (ICP) etching device, feeding HBr into the etching chamber as an etching gas, and controlling the flow rate of the HBr to 150 sccm, and , controlling the pressure in the etching chamber to be 60 mtorr, converting the etching gas into plasma with a plasma power source with a power of 550W, and applying a bias voltage of 250V on the AlGaN material, and making The plasma is in contact with a selected area on the surface of the AlGaN material, thereby realizing the etching of the selected area of the AlGaN material, the etching time is 30 seconds, and the etched AlGaN material is recorded as sample 1; in this embodiment, the etching parameters and Table 1 shows the surface roughness of the etched AlGaN material.

Example 2

A kind of etching method of AlGaN material, comprises the steps:

The AlGaN material is placed in the etching chamber of the inductively coupled plasma etching (ICP) etching equipment, and SF ₆ is introduced into the etching chamber as an etching gas, and the flow rate of the SF ₆ is controlled to be 150 sccm , and, controlling the pressure in the etching chamber to be 60 mtorr, converting the etching gas into plasma with a plasma power source with a power of 550W, and applying a bias voltage of 250V on the AlGaN material, And make the plasma contact with the selected area on the surface of the AlGaN material, so as to realize the etching of the selected area of the AlGaN material, the etching time is 30S, and the AlGaN material after etching is recorded as sample 2; in this embodiment, the etching The parameters and the surface roughness of the AlGaN material after etching are shown in Table 1.

Example 3

A kind of etching method of AlGaN material, comprises the steps:

The AlGaN material is placed in an etching chamber of an inductively coupled plasma etching (ICP) etching device, and HBr and SF ₆ are introduced into the etching chamber as etching gases, wherein the HBr is the main etching chamber Etching gas, SF ₆ is an auxiliary etching gas, and the flow rate of controlling the HBr is 150 sccm, the flow rate of SF ₆ is 25 sccm, and the pressure in the etching chamber is controlled to be 60 mtorr, with a power of 550W plasma The power source converts the etching gas into plasma, and applies a bias voltage of 250V on the AlGaN material, and makes the plasma contact with a selected area on the surface of the AlGaN material, thereby realizing the selection of the AlGaN material. For the etching of the region, the etching time is 30 seconds, and the etched AlGaN material is recorded as sample 3; the etching parameters and the surface roughness of the etched AlGaN material in this embodiment are shown in Table 1.

Example 4

A kind of etching method of AlGaN material, comprises the steps:

The AlGaN material is placed in an etching chamber of an inductively coupled plasma etching (ICP) etching equipment, and HBr and _O2 are introduced into the etching chamber as etching gases, wherein the HBr is the main etching chamber Etching gas, O ₂ is auxiliary etching gas, and the flow rate of controlling the HBr is 150 sccm, the flow rate of O ₂ is 25 sccm, and the pressure in the etching chamber is controlled to be 60 mtorr, and the power is 550 W plasma power The source converts the etching gas into plasma, and applies a bias voltage of 250V on the AlGaN material, and makes the plasma contact with a selected area on the surface of the AlGaN material, thereby realizing the selected area of the AlGaN material The etching time is 30 seconds, and the etched AlGaN material is recorded as sample 4; the etching parameters and the surface roughness of the etched AlGaN material in this embodiment are shown in Table 1.

Example 5

A kind of etching method of AlGaN material, comprises the steps:

The AlGaN material is placed in an etching chamber of an inductively coupled plasma etching (ICP) etching device, and SF ₆ and O ₂ are introduced into the etching chamber as etching gases, wherein the SF ₆ is The main etching gas, O ₂ is the auxiliary etching gas, and the flow rate of the SF ₆ is controlled to be 150 sccm, the flow rate of the O ₂ is 25 sccm, and the pressure in the etching chamber is controlled to be 60 mtorr, and the power is 550W The plasma power source converts the etching gas into plasma, and applies a bias voltage of 250V on the AlGaN material, and makes the plasma contact with a selected area on the surface of the AlGaN material, thereby realizing the AlGaN material For the etching of the selected area, the etching time is 30 seconds, and the etched AlGaN material is recorded as sample 5; the etching parameters and the surface roughness of the etched AlGaN material in this embodiment are shown in Table 1.

Example 6

A kind of etching method of AlGaN material, comprises the steps:

The AlGaN material is placed in an etching chamber of an inductively coupled plasma etching (ICP) etching device, and HBr, O ₂ and SF ₆ are introduced into the etching chamber as etching gases, wherein the HBr Main etching gas, O ₂ and SF ₆ are auxiliary etching gases, and the flow rate of HBr in which is controlled is 150 sccm, and the flow rate of O ₂ and SF ₆ mixed gas is 25 sccm, and, controlling the flow rate in the etching chamber The pressure is 60 mtorr, the etching gas is converted into plasma with a plasma power source of 550W, and a bias voltage of 250V is applied to the AlGaN material, and the plasma and the surface of the AlGaN material are The selected area is contacted, so as to realize the etching of the selected area of the AlGaN material, the etching time is 30S, and the etched AlGaN material is recorded as sample 6; the etching parameters and the surface roughness of the etched AlGaN material in this embodiment As shown in Table 1 and FIG. 3 , it can be seen from FIG. 3 that the surface of the etched AlGaN material in this embodiment is flat.

It should be noted that the auxiliary etching gas in this embodiment is to first mix _O2 and _SF6 according to the molar ratio of 1.5:1 to form a mixed gas, and then pass the mixed gas and HBr gas into the etching chamber together as an etching gas.

Example 7

A kind of etching method of AlGaN material, comprises the steps:

The AlGaN material is placed in an etching chamber of an inductively coupled plasma etching (ICP) etching device, and HBr, O ₂ and SF ₆ are introduced into the etching chamber as etching gases, wherein the HBr Main etching gas, O ₂ and SF ₆ are auxiliary etching gases, and the flow rate of HBr in which is controlled is 150 sccm, and the flow rate of O ₂ and SF ₆ mixed gas is 25 sccm, and, controlling the flow rate in the etching chamber The pressure is 60 mtorr, the etching gas is converted into plasma with a plasma power source of 550W, and a bias voltage of 250V is applied to the AlGaN material, and the plasma and the surface of the AlGaN material are The selected area is contacted, so as to realize the etching of the selected area of the AlGaN material, and the etching time is 30S; the etched AlGaN material is recorded as sample 7; the etching parameters and the surface roughness of the etched AlGaN material in this embodiment As shown in Table 1.

It should be noted that the auxiliary etching gas in this embodiment is to first mix _O2 and _SF6 according to the molar ratio of 1.8:1 to form a mixed gas, and then pass the mixed gas and HBr gas into the etching chamber together as an etching gas.

Example 8

A kind of etching method of AlGaN material, comprises the steps:

The AlGaN material is placed in an etching chamber of an inductively coupled plasma etching (ICP) etching device, and HBr, O ₂ and SF ₆ are introduced into the etching chamber as etching gases, wherein the HBr Main etching gas, O ₂ and SF ₆ are auxiliary etching gases, and the flow rate of HBr in which is controlled is 150 sccm, and the flow rate of O ₂ and SF ₆ mixed gas is 25 sccm, and, controlling the flow rate in the etching chamber The pressure is 60mtorr, the plasma power source with a power of 550W is used to convert the etching gas into plasma, and a bias voltage of 250V is applied to the AlGaN material, and the selective contact between the plasma and the surface of the AlGaN material In order to realize the etching of the selected area of the AlGaN material, the etching time is 30 seconds; the etched AlGaN material is recorded as sample 8; the etching parameters and the surface roughness of the etched AlGaN material in this embodiment are as follows: Table 1 shows.

It should be noted that the auxiliary etching gas in this embodiment is to first mix _O2 and _SF6 according to the molar ratio of 2:1 to form a mixed gas, and then pass the mixed gas and HBr gas into the etching chamber together as an etching gas.

Example 9

A kind of etching method of AlGaN material, comprises the steps:

The AlGaN material is placed in an etching chamber of an inductively coupled plasma etching (ICP) etching device, and HBr, O ₂ and SF ₆ are introduced into the etching chamber as etching gases, wherein the HBr Main etching gas, O ₂ and SF ₆ are auxiliary etching gases, and the flow rate of HBr in which is controlled is 220 sccm, and the flow rate of O ₂ and SF ₆ mixed gas is 25 sccm, and, controlling the flow rate in the etching chamber The pressure is 60 mtorr, the etching gas is converted into plasma with a plasma power source of 550W, and a bias voltage of 250V is applied to the AlGaN material, and the plasma and the surface of the AlGaN material are The selected area is contacted, so as to realize the etching of the selected area of the AlGaN material, and the etching time is 30S; the etched AlGaN material is recorded as sample 9; the etching parameters and the surface roughness of the etched AlGaN material in this embodiment As shown in Table 1.

It should be noted that the auxiliary etching gas in this embodiment is to first mix _O2 and _SF6 according to the molar ratio of 1.8:1 to form a mixed gas, and then pass the mixed gas and HBr gas into the etching chamber together as an etching gas.

Example 10

A kind of etching method of AlGaN material, comprises the steps:

The AlGaN material is placed in an etching chamber of an inductively coupled plasma etching (ICP) etching device, and HBr, O ₂ and SF ₆ are introduced into the etching chamber as etching gases, wherein the HBr The main etching gas, O ₂ and SF ₆ are auxiliary etching gases, and the flow rate of HBr in the control is 70 sccm, and the flow rate of O ₂ and SF ₆ mixed gas is 25 sccm, and, controlling the flow rate in the etching chamber The pressure is 60 mtorr, the etching gas is converted into plasma with a plasma power source of 550W, and a bias voltage of 250V is applied to the AlGaN material, and the plasma and the surface of the AlGaN material are The selected area is in contact, so as to realize the etching of the selected area of the AlGaN material; the etched AlGaN material is recorded as sample 10; the etching parameters and the surface roughness of the etched AlGaN material in this embodiment are shown in Table 1 .

It should be noted that the auxiliary etching gas in this embodiment is to first mix _O2 and _SF6 according to the molar ratio of 1.8:1 to form a mixed gas, and then pass the mixed gas and HBr gas into the etching chamber together as an etching gas.

Example 11

A kind of etching method of AlGaN material, comprises the steps:

The AlGaN material is placed in an etching chamber of an inductively coupled plasma etching (ICP) etching device, and HBr, O ₂ and SF ₆ are introduced into the etching chamber as etching gases, wherein the HBr Main etching gas, O ₂ and SF ₆ are auxiliary etching gases, and the flow rate of HBr in which is controlled is 150 sccm, and the flow rate of O ₂ and SF ₆ mixed gas is 25 sccm, and, controlling the flow rate in the etching chamber The pressure is 60 mtorr, the etching gas is converted into plasma with a plasma power source of 550W, and a bias voltage of 250V is applied to the AlGaN material, and the plasma and the surface of the AlGaN material are The selected area is in contact, so as to realize the etching of the selected area of the AlGaN material, and the etched AlGaN material is recorded as sample 11; the etching parameters and the surface roughness of the etched AlGaN material in this embodiment are shown in Table 1 .

It should be noted that, the auxiliary etching gas in this embodiment is first mixed with O ₂ and SF ₆ at a molar ratio of 1:2 to form a mixed gas and then passed into the etching chamber.

Example 12

A kind of etching method of AlGaN material, comprises the steps:

The AlGaN material is placed in the etching chamber of the inductively coupled plasma etching (ICP) etching equipment, and HBr, O ₂ and SF ₆ are mixed into the etching chamber according to the molar ratio of 20:1.8:1 to form The mixed gas is used as the etching gas, and the flow rate of the mixed gas is controlled to be 150 sccm, and the pressure in the etching chamber is controlled to be 60 mtorr, and the etching gas is converted into plasma by a plasma power source with a power of 550W body, and a bias voltage of 250V is applied to the AlGaN material, and the plasma is brought into contact with a selected area on the surface of the AlGaN material, so as to realize etching of the selected area of the AlGaN material, and the etching time is 30S, The etched AlGaN material is recorded as sample 12; the etching parameters and the surface roughness of the etched AlGaN material in this embodiment are shown in Table 1.

By the SEM surface observation of the different samples obtained in Examples 1-12 and the measurement of the surface roughness, for ease of comparison, the average value of the roughness of the selected sample 1 is 1, and all the other samples are the same as the roughness of the sample 1. The ratio of roughness can directly reflect the relationship between the etched morphology and roughness.

Table 1 shows the main etching parameters for dry etching of AlGaN materials in Examples 1-12 and the morphology characterization after etching

From the comparative experimental results shown in Table 1, it can be seen that in the same etching time, comparing sample 1 and sample 2, it can be seen that the etching rate using _SF6 as the etching gas is greater than that of using HBr as the etching gas. speed, but etching with SF ₆ will increase the surface roughness of the etched area of the AlGaN material, and will cause damage to the sidewall of the etched area, forming a rough surface; comparative sample 1 and sample 4, sample 2 and sample 5, it can be seen that the addition of O ₂ can reduce the roughness of the etched area of the _AlGaN material to a certain extent, and improve the smoothness of the sidewall morphology of the etched area; The etching speed can be increased, but the surface roughness of the etched area of the AlGaN material will be increased.

Comparing sample 4 and sample 6, it can be seen that although the roughness of the AlGaN material etching area of sample 4 without SF ₆ is the smallest and the surface is the smoothest, its etching speed is slower. In the same time, embodiment 6 The etching rate (etching depth) in is 1.68 times that of Example 4.

Compared with Example 6, Example 7 increases the amount of _O2 , therefore, the etching depth of sample 7 is increased, and the etching roughness is reduced, because the addition of _O2 can improve the oxidation performance , improved the etching rate, and improved the smoothness of the surface; and comparative example 8, further increasing the amount of O ₂ , did not further increase the etching rate, because too much O ₂ diluted SF ₆ , SF ₆ The probability of contact with AlGaN material is reduced, which in turn reduces the etch rate.

Comparing Example 9 and Example 10, by increasing the flow rate of HBr (sample 9) and reducing the flow rate of HBr (sample 10), and changing the flow rate of the main etching gas, it will not simply increase or decrease the etching rate, and also affects the roughness of the etched surface, the roughness of sample 9 is obviously improved, and although the roughness of sample 10 in embodiment 10 is less than the roughness of sample 7 in embodiment 7, the etching The speed is significantly reduced a lot.

Comparing Examples 6-8 with Example 11, the _SF content in the etching gas of Example 11 is higher, but Example 11 does not significantly improve the rate of etching, but the sample in Example 11 The roughness of 11 is greatly increased. This is because when the content of SF ₆ increases and the content of O ₂ decreases, the etching of SF 6 will increase the roughness due to the decrease of the oxidation of the surface, but the etching of SF ₆ will increase the roughness due to the decrease of the oxidation of O ₂ . The erosion rate did not increase substantially.

Comparing Example 12 with Examples 6-11, it is found that HBr, O ₂ and SF ₆ are mixed and then passed into the etching equipment together as an etching gas, and the etching gas is formed into a plasma for etching , taking the comparison with Example 7 as an example, both the etching rate and the etching roughness in Example 12 are reduced, because the main etching gas and the auxiliary etching gas are pre-mixed and fed together. In the ICP etching device, since the relative molecular weight of SF ₆ is much larger than that of HBr and O ₂ , although the gas has been mixed before being passed into the etching chamber, the SF ₆ with a large relative molecular weight will go down Shen, thick in the etching chamber, SF ₆ is under the mixed gas, and when it is converted to form plasma, it will delay the formation of plasma compared with the other two gases, which will make the etching rate somewhat slow down, which is not conducive to the improvement of the etching rate, and when the mixed gas of SF ₆ and O ₂ and HBr are introduced respectively, because the pipeline of SF ₆ is different from the pipeline of the main etching gas, in the etching chamber When the gas is formed into a plasma, the gas in each pipeline is passed into the etching chamber, and the plasma can be formed rapidly without the sinking of SF ₆ , so the etching rate will not be affected.

In summary, when considering the etching rate and the flatness of the etching surface, O2 and _SF6 are mixed according to the molar ratio _of 1.8:1 to form a mixed gas and then passed into the etching chamber to etch best effect.

An etching method for an AlGaN material provided in an embodiment of the present invention uses an etching gas that does not contain chlorine to etch AlGaN, comprehensively compares different etching samples, uses HBr as the main etching gas, and uses O ₂ and SF ₆ As an auxiliary etching gas, it can balance the etching speed and etching surface smoothness, thereby improving the etching speed and etching quality of the AlGaN material.

It should be noted that due to the different etching chambers, etching conditions and by-products produced during the etching process for different substances (such as silicon or germanium or arsenic system substances), the embodiments of the present invention are aimed at AlGaN substances The improvement of defects with specific by-products during ICP etching is proposed differently from the etching of other material systems.

An AlGaN material etching method provided in an embodiment of the present invention uses a specific ratio of O ₂ and SF ₆ as an auxiliary etching gas to cooperate with the main etching gas, which can not only prevent the formation of etching residues but also remove the etching residues. Etching residues, forming a flat etching surface, will not affect the etching rate, and, in the etching process, do not use Cl-containing etching gas, so that it will not form difficult-to-remove AlGaCl _x raised residues , thereby improving the quality of etching.

It should be understood that the above-mentioned embodiments are only to illustrate the technical concept and features of the present invention, the purpose of which is to enable those skilled in the art to understand the content of the present invention and implement it accordingly, and not to limit the protection scope of the present invention. All equivalent changes or modifications made according to the spirit of the present invention shall fall within the protection scope of the present invention.

Claims (8)

1. an etching method of AlGaN material, it is characterized in that comprising: O in advance ₂ and SF ₆ mixed to form mixed gas, then with described mixed gas and HBr gas as etching gas, O in described mixed gas ₂ and The molar ratio of _SF6 is (1.5-2):1; The etchant gas is converted into a plasma, and the plasma is contacted with an AlGaN material. 2. The etching method of AlGaN material according to claim 1, characterized in that: the molar ratio of the HBr gas to the mixed gas formed by _O2 and _SF6 is (6-25): (1-4) . 3. The etching method for AlGaN material according to claim 1, characterized by comprising: converting the etching gas into plasma by using a plasma power source with a power of 500-800W. 4. An etching method for an AlGaN material, characterized in that it comprises: placing the AlGaN material in an etching chamber of an etching device; First mix _O2 and _SF6 to form a mixed gas, then use the mixed gas and HBr gas as an etching gas to pass into the etching chamber, and use a plasma power source to convert the etching gas into plasma , and then the plasma is brought into contact with a selected area on the surface of the AlGaN material, wherein the molar ratio of O ₂ and SF ₆ in the mixed gas is (1.5-2):1. 5. The etching method of AlGaN material according to claim 4, is characterized in that specifically comprising: Introduce described etching gas into described etching chamber, control wherein the flow rate of HBr gas is 80-200sccm, the flow rate of mixed gas formed by _O2 and _SF6 is 10-40sccm, and the flow rate of carrier gas is 80-200sccm. 400 sccm, And, control the pressure in the etching chamber to be 20-80mtorr, convert the etching gas into plasma with a plasma power source with a power of 500-800W, and apply 200-300V to the AlGaN material bias voltage and bring the plasma into contact with selected regions of the surface of the AlGaN material. 6. The etching method according to claim 4 or 5, characterized in that: the molar ratio of the HBr gas to the mixed gas formed by O ₂ and SF ₆ is (6-25):(1-4). 7. The etching method of the AlGaN material according to claim 5, further comprising: placing the AlGaN material in the etching chamber of the etching equipment, and raising the temperature in the etching chamber to 500 -600°C, then use nitrogen gas to blow the surface of the AlGaN material to complete the surface cleaning treatment of the AlGaN material, and then etch the AlGaN material. 8. A method for manufacturing an AlGaN device, characterized in that it comprises: a step of dry etching the AlGaN layer in the AlGaN device by the etching method for the AlGaN material according to any one of claims 1-7 .

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