JPS6024012A - Activating method for ion implanted substrate - Google Patents

Abstract

PURPOSE:To obtain high activation factor by applying a liquid containing organic silicon compound of the predetermined main surface of a substrate implanted with ions, heat treating it to obtain silicon bioxide, and further heat treating the same at higher temperature. CONSTITUTION:A liquid containing organic silicon compound is applied on the main surface of a substrate of a III-V group compound semiconductor implanted with ion. Then this substrate is heat treated to change the liquid containing organic silicon compound to silicon bioxide. The substrate is further treated at higher temperature than that of the prior heat treatment. The III-V group compound of the semiconductor is preferably gallium arsenide or indium phosphide. Silicon or selenium ion is preferred as the ions to be implanted. In such a manner, high activation factor can be obtained without any use of dangerous gas or any special CVD device.

Description

[Detailed Description of the Invention] Industrial Field of Application The present invention relates to ion implantation, which is an important process in manufacturing field effect transistors (FETs), integrated circuits, etc. using I[LV compound semiconductors]. This invention relates to a method for activating ionic species.

Here, some explanation will be added regarding the m-v group compounds.

A 1=1 compound of a group ■ element and a group ■ element in the periodic table of elements is called a ■-■ group compound.

Most of these are semiconductor-like. ■What is a genus element?
Specifically, boron (element symbol B), aluminum (mul)
), gallium (crt), indium A (In), and group II elements include nitrogen (6), phosphorus (t), arsenic (mus), and antimony (sb).

In the present invention, the ■-■ group compound semiconductor mainly refers to gallium arsenide (GaAs) and indium phosphide (InP).

Conventional Structures and Problems There are two main methods for activating ion species implanted into conventional ■-■ group compound semiconductors.

The first is called capless annealing. That is, substrates of the same type (referred to as dummy wafers) are stacked in contact with the implanted surface of the substrate, and then heat-treated in a hydrogen atmosphere, an inert atmosphere such as argon, or an atmosphere of group V elements. Ru. Here, the atmosphere of group Ⅰ elements refers to an atmosphere in which a partial pressure of phosphine (PH3) or arsine (AsH3) exists.

The problems with this activation method are as follows. Regarding the above hydrogen atmosphere or inert atmosphere, the atoms of the group (■) of the group (■-V) evaporate, causing a deviation from the (s)4 chiometry (stoichiometric equilibrium) near the surface of the substrate, and implantation. This disturbs the reproducibility of the activity of the ionic species, and furthermore, the smoothness of the substrate surface is disturbed, which is completely undesirable for FET or integrated circuit manufacturing processes. Furthermore, when heat treatment is carried out in an atmosphere of group III elements, phosphine (PH3) or arsine (
Mu5H3) is so poisonous that it can be life-threatening in just a few pP'ml in a few hours. 7. It is extremely difficult to handle.

The second conventional method is called cap annealing. That is, silicon dioxide (5 in 2
) or coated with silicon nitride and heat treated in a hydrogen atmosphere or a neutral atmosphere such as argon. In this case, silicon oxide is formed by chemical vapor deposition (CVN) or sputtering, and silicon nitride is formed by plasma/CVN or CVN.
Formed by the n method.

In this activation method, 1. C'VD equipment and plasma/CVD
Equipment and sputtering equipment are required.1. Establishing this process requires a large amount of investment. Furthermore, in the sputtering method and the plasma CVD method, the ion bombardment seems to cause considerable damage to the sea urchins, .

The present invention is related to the second conventional method, and is an improvement on this.

Purpose of the invention The purpose of the present invention is to avoid the use of dangerous gases and to
The use of ionic species in ion-implanted ■-■ compound semiconductor wafers makes it possible to obtain high activation rates and, in some cases, high carrier mobilities without the need for vn or sputtering equipment. An activation method is provided.

Structure of the Invention The method of activating an ion-implanted substrate provided by the present invention includes a first step of applying a liquid containing an organosilicon compound to the main surface of an ion-implanted group IX-III compound semiconductor substrate; The second step is to heat-treat the liquid to turn the liquid into silicon dioxide, and the third step is to heat-treat the substrate at a higher temperature than the temperature during the heat treatment.

The present invention further provides a first method of applying a liquid containing an organic silicon compound and an organic compound of at least one element among the constituent elements of the m-v group compound semiconductor to the entire surface of the substrate or to the ion-implanted surface. a second process of heat treatment;
The method further comprises a third step of heat treatment at a higher temperature than the heat treatment, and the liquid becomes silicon dioxide containing the at least one element in the second step. It concerns a method of activating implanted ionic species in a semiconductor substrate.

These activation methods allow the release of dangerous gases and special CVNs.
It is possible to obtain high activation rates and in some cases high carrier mobilities without the need for equipment or spuck equipment.

In the present invention, in particular, gallium arsenide (GaAg) l indium phosphide (InP) is used as the ■-■ group compound semiconductor.
) was effective.

The ion species include silicon (Si) ions and selenium (B).
e) ion, beryllium (Be) ion.

It was effective when it was a magnesium (Mg) ion. In the case of sulfur ions, as in the conventional case, there is considerable diffusion, which is somewhat inconvenient.

The heat treatment of the second step has the purpose of vitrifying the applied liquid, ie, converting it into glassy silicon dioxide.

It is desirable that the temperature in the second step is 500°C or less. If this temperature is 600° C. or higher, the surface of the ■-■ group compound semiconductor substrate becomes rough during the heat treatment in the second step. Furthermore, the activation rate of the implanted ion species also decreases. From this point of view, the temperature is more preferably 450°C or lower. Further, the lower limit temperature of the second process is determined by the lower limit temperature at which the applied liquid becomes vitrified.

There are no particular restrictions on the atmosphere for the second process, but clean air or nitrogen is most easily used.

The organic compound of the one element contained in the liquid refers to μ in the case where the ■-■ group compound semiconductor is gallium arsenide, an organic compound of gallium, or an organic compound of arsenic; When the Group (1) compound semiconductor is indium phosphide, it refers to an organic compound containing phosphorus or an organic compound of indium.

The coating in the first step may include a spin coating method using a spinner, immersion in the liquid, and then removing the semiconductor substrate from the liquid, but the present invention is not limited to these methods. Not.

The method using a spinner is superior because of the uniformity of the film thickness.

A desirable film thickness of the silicon dioxide is 1α Angstrom or more. Below this, the third
During this process, surface roughness occurs and the activation rate also deteriorates. The upper limit of the desired film thickness is rather limited by the method of application described above. In order to suppress cracking and peeling of the silicon dioxide film, the thickness should be approximately 5,000.8 or less.

The third step of heat treatment is performed to activate the ion species implanted into the substrate. In order to realize the present invention,
The heat treatment method in the third step may be a heat treatment method using a furnace or a method using light energy irradiation using a lamp. Desirably, the activation rate of the implanted ionic species is improved by the heat treatment using the lamp at a higher temperature and for a shorter time than by the heat treatment method using the furnace. The atmosphere for the heat treatment in the third step may be any inert atmosphere such as nitrogen, hydrogen, or argon. The desirable temperature for heat treatment in a furnace varies depending on the type of ions to be implanted, but is generally as reported in the past, and ranges from 6oO to 10oO.
It is in the range of 00℃. In the case of heat treatment using light irradiation from a lamp, the desired temperature of the irradiated substrate is 1° below the above temperature.
℃ considerably high.

Description of examples Examples of the present invention will be specifically described below.

[4] Semiconductor substrate to be ion-implanted (100) plane, 2 inch diameter, 2 circles, 2 single-sided polished chromium cswppm
A semi-insulating gallium arsenide substrate containing iron and a semi-insulating indium phosphide substrate containing nine-dashi iron, similar to Habo, were prepared. 1st
In the substrate column of the table, the gallium arsenide substrate is expressed as GaAs, and the indium phosphide is expressed as InP.

The ion implantation was performed using a model 400-10 implanter manufactured by Exterion.

(Left below) Silicon fluoride (L) is used as the source for S1 ion implantation.
liiF4), selenium hydride (SeH2) was used as a source for Se ion implantation, and solid magnesium (Mg) metal was used as a - ion implantation source. Regarding the implantation of ions, an aperture made of Be was sputtered with boron ions to extract Be ions. In addition, when implanting Se ions and ■ ions, the substrate is
It was set to 'C'.

Immediately before ion implantation, the substrate was etched by several μm using a mixture of sulfuric acid, hydrogen peroxide, and pure water to remove the polished layer.

As an example, a summary is summarized in Table 1. Two similar boards were used per each loft.

Several hundred Schottky junctions, or measurement points, are formed on each substrate. Each Schottky junction is formed by evaporating aluminum (AI) using a vacuum evaporation method after activation by ion implantation and heat treatment. The ohmic electrode used an alloy of gold (U) and germanium (-). The carrier concentration profile is measured using MI-383 manufactured by Sanwa Musen Instrument Research Institute, and the number of activated carriers is calculated by integrating the profile. The activation rate of each position is calculated from this result and the implantation dose. The activation rates ','-tar in Table 1 are the average values for the two substrates.

Numbers 1 to 12 in Table 1 are comparative examples based on conventional examples. That is, after implantation, a silicon dioxide film with a thickness of 2,000 yen was applied to the implanted surface of the substrate using Kokusai Electric Co., Ltd.
The substrate temperature was 300° C. using a reduced pressure CVN device D J-8300 manufactured by K., K., Ltd. Thereafter, the third step of heat treatment, that is, activation of the implanted ions, is performed in an electric furnace in a hydrogen stream. The average activation rate at this time is the first
It is as shown in the table.

In Table 1, loft numbers 13 to 16 are methods for applying the liquid containing the organosilicon compound to the substrate.
This is the result of adopting a method using a spinner and a method of directly immersing the substrate in the liquid. Spinner Mikasa (K)
, K) Spinner II-DS was used, and the number of rotations was 300.
The 0 rotation/rotation rotation time was 20 seconds. A gallium arsenide (CRA) substrate was used as the substrate, and Si ions were implanted at doses of 6×1012/c4 and 5×1013/cd. As the liquid, 00D-Si manufactured by Tokyo□Ohka Kogyo Co., Ltd.
00CD using -85000 is silanol, 5
i-(OH)4 and additives are dissolved in an organic solvent. Vitrification of the applied OCD begins at about 306°C. In the example, the heat treatment for vitrification of the coating film, that is, the heat treatment in the second step, was carried out in a nitrogen stream for 3
This was carried out at 50°C for 20 minutes. The film thickness at this stage is 1500~
There were 2000 people. Next, in order to compare with the comparative example,
The third step of heat treatment was performed in an electric furnace at 860° C. for 20 minutes in a hydrogen stream. It can be seen that the active method according to the present invention is relatively superior to the comparative example.

Next, Table 1 shows lot numbers 17 to 23 of the results obtained when the substrate was made of gallium arsenide (GaAs) or indium phosphide (InP) and the implanted ions and dose were varied. The liquid containing the organosilicon compound was 0CD-5i-85060, and the heat treatment temperature and time in the third step were determined for comparison with the comparative example. The liquid was applied using a spinner, and the third step of heat treatment was performed using an electric furnace in a hydrogen stream. Other details are the same as above.

From experiments corresponding to lot numbers 17 to 2S in Table 1, it was found that when gallium arsenide (AAS) or indium phosphide (Inj) is used as a substrate, even if the implanted ions and dose were varied, the activity according to the present invention was The chemical method is superior to the comparative example.

Next, as the liquid to be applied, an organic silicon compound and 3-6
Results obtained using a liquid containing an organic compound of one of the constituent elements of a compound semiconductor are shown in lot numbers 24 to 35 in Table 1. The operating conditions for each loft are as shown in Table 1.

However, as the liquid, OCD-Ga-69310, OCD-, As- manufactured by Tokyo Ohka Kogyo (LK)
Ei931010 Cj D-P-tsetslo was used.

The methods corresponding to lot numbers 24 to 36 in Table 1 are not only considerably superior to the comparative example in terms of activation rate, but also
The activation rate of implanted ions is superior to the case where OGD-Si-85000 is used as the liquid. In other words, it is more desirable to use a liquid that also contains an organic compound and an organic compound containing one of the constituent elements of the 3-6 compound semiconductor, rather than a liquid that contains only the organosilicon compound. .

I'll make some comments here. OCD-Ga-59310
is the silanol and organic gallium (Ga) compound,
OCD-Mu5-59310 contains the silanol and an organic arsenic (S) compound, and OCD-P-59510 contains the silanol and an organic phosphorus (P) compound.

Although not listed in Table 1, gallium arsenide (Ga
Using the As) substrate, the OCD-()a-593
10 and the above 0 (D-Suke-59310) were mixed at a volume ratio of 1:1, and an experiment similar to the above was conducted using this as the liquid, the activation rate was lower than that of the comparative example. I improved by about 3 to 6 inches.

Next, the results obtained when the heat treatment temperature in the second step was varied are shown in Table 1, lot numbers 36 to 42.

The substrate was made of Gaps, Si ions were implanted, and the liquid was prepared using 00D-8i-86 manufactured by Tokyo Ohka Kogyo (K, K).
000 was used, and the heat treatment temperature in the second step was varied from 150°C to 550''C.Other conditions were as described above.From Table 1, the heat treatment temperature in the second step The activation rate is highest at 350°C. When the heat treatment temperature is 150°C, the coating film is not sufficiently vitrified, and this affects the activation rate of implanted ions to be extremely low. If the heat treatment temperature is set to 500'C or more, the substrate becomes rough at this point and the activation rate decreases.

For the heat treatment method in the third step, we adopted a method using electric furnace heating and a method using rapid heating by light irradiation with a lamp.
The results of implementing the present invention are shown in Table 1, lot number 43.
~67.

R made by Shinku Riko (K,, K) using the above-mentioned lamp.
A schematic cross-sectional view of a rapid heating device using HL-P65 is shown in FIG. In Figure 1, 1 is an aluminum block, 2 is a polished gold-coated reflective surface, and 3 is a polished gold-coated reflective surface.
is a 1.2KW rated infrared lamp, 4 is a transparent quartz tube, 6 is
1 is a substrate holder made of molybdenum (MO), 6 is a substrate to be heat treated, and 7 is the vitrified coating liquid. In this figure, the implanted surface is the top surface of the substrate.

Next, FIG. 2(M) shows the temperature increase characteristics in the case of heating with an electric furnace, and FIG. 2(B) shows the temperature increase characteristics in the case of rapid heating with a lamp. In the case of heating with an electric furnace, the substrate is first inserted into the core tube of the electric furnace at a position maintained at a predetermined heat treatment temperature, and is held in that position for a predetermined heat treatment time. The board is pulled out. FIG. 2(A) shows the results of measuring the relationship between the temperature near the substrate and time after inserting the substrate using a thermocouple. Figure 2 (B) shows the results of using a thermocouple to measure the relationship between the temperature near the substrate and time after the substrate was placed in the quartz tube shown in Figure 1 and power was supplied to the lamp. be.

In Figure 2, the vertical axis is the measured temperature near the substrate, and the horizontal axis is (
A) shows the time since the substrate was installed at a predetermined temperature position in the reactor core tube, and (B) shows the time after power was supplied to the lamp. FIG. 2(A) corresponds to what was done in a hydrogen stream, and FIG. 2(B) corresponds to what was done in a nitrogen stream. Figure 2 (A), (B
), we would like to pay attention to the scale on the horizontal axis.

It is understood how the lamp heating method is capable of rapid heating.

The heat treatment methods using lamps corresponding to loft numbers 46 to 61 and lot numbers 66 to 67 in Table 1, which were carried out here, will be briefly described. The heat treatment temperature in the third step in Table 1 is:
This corresponds to the peak temperature in FIG. 2(B). Further, as a heat treatment method, as shown in FIG. 2 ω), when the peak temperature is reached, the power supplied to the lamp is momentarily cut off. Therefore,
The temperature history that the substrate to be heat treated is subjected to is as described in the second report)
It will be like this.

Regardless of whether the heat treatment method in the third step from Table 1 is a method using an electric furnace or a method using rapid heating with a lamp, the activation rate will be lower than that of the comparative example at the optimal heat treatment temperature for this process. expensive. The results when using two electric furnaces,
Comparing the results of rapid heating with a lamp, it is found that the activation rate is higher in the case of rapid heating with a lamp, and that the optimum heat treatment temperature is about 100° C. higher in the case of rapid heating with a lamp.

In the above example, the substrate was made of gallium arsenide (mzAl+ The present invention is also effective for the following.

Effects of the Invention As is clear from the above explanation, the present invention can obtain an improved activation rate of implanted ions in an Ifl-■ group compound substrate compared to the conventional method. Furthermore, the present invention is characterized in that a silicon dioxide film is formed using a spinner or immersion when activating the implanted ions, and therefore, unlike conventional methods, a CVD device or sputtering device is not required.
Therefore, it is highly economical.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a lamp heat treatment apparatus used in the activation method of the present invention, and FIG. 2 is a characteristic diagram showing temperature characteristics over time during heat treatment using an electric furnace and heat treatment using a lamp. 1... Aluminum block, 2...
・Reflective surface, 3... Infrared lamp, 4...
Transparent quartz tube, 6...Substrate holder, 6...
... Ion-implanted semiconductor substrate, 7... Vitrified coating liquid. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Picture string installation plaster 1 Sakima Ranbuhimui! j, #Reiken/+1 interval

Claims (1)

[Claims] (1) A first step for applying a liquid containing a main in+lcfM silicon compound to an ion-implanted IV group compound semiconductor substrate.
Activation of an ion-implanted substrate, comprising: a second step of heat-treating the substrate to convert the liquid into silicon dioxide; and a third step of heat-treating the substrate at a higher temperature than the temperature during the heat treatment. cation law. (2) The method for activating an ion-implanted substrate according to claim 1, characterized in that gallium arsenide or indium phosphide is used as the III-V compound. (3) The method for activating an ion-implanted substrate according to claim 1, wherein in the third step, heat treatment is performed by irradiation with light energy from a lamp. (4) In the first step, in the ion-implanted ■-■ group compound semiconductor substrate, the implanted ion species are silicon ions and heptadium ions. A method for activating an ion-implanted substrate according to claim 1, characterized in that beryllium ions and magnesium ions are used. (5) Applying a liquid containing an organic silicon compound and an organic compound of at least one element among the constituent elements of the ■-■ group compound semiconductor to the main surface of the ion-implanted ■-■ group compound semiconductor substrate. a first step, and a second step of heat-treating the substrate to make the liquid mainly silicon dioxide;
and a third step of heat treating the substrate at a higher temperature than the temperature during the heat treatment. (e) The method for activating an ion-implanted substrate according to claim 5, characterized in that gallium arsenide or indium phosphide is used as the Ill-V group compound. ('7) The method for activating an ion-implanted substrate according to claim 6, wherein in the third step, heat treatment is performed by irradiation with light energy from a lamp. (8) In the first step, the ion species implanted in the ■-■ group compound semiconductor substrate include silicon ions and selenium ions. 7. The method for activating an ion-implanted substrate according to claim 6, characterized in that beryllum ions and magnesium ions are used.