JPH0563181A - Optical integrated device and manufacturing method thereof - Google Patents

Abstract

(57) [Abstract] [Object] The present invention relates to an optical integrated device formed on a semi-insulating semiconductor substrate and a method for manufacturing the same, and particularly to the introduction of damage due to the difference in the manufacturing process of each semiconductor device that constitutes the optical integrated device. It is an object of the present invention to provide a high-performance optical integrated device which is free from performance deterioration due to the above and a manufacturing method thereof. [Structure] In an example of the present invention, a semi-insulating semiconductor substrate (9)
A first semiconductor multilayer film (4 to 8) constituting a first semiconductor element, and a protective layer (3) made of a semiconductor on the first semiconductor multilayer film (4 to 8). A first step of growing a second semiconductor multilayer film (1-2) constituting a second semiconductor element on the protective layer (3), and a second semiconductor multilayer film (1-2) And the first semiconductor multilayer film (4 to
8) a second step of exposing the first semiconductor multilayer film (4 to 8) while leaving the protective layer (3) on the first semiconductor multilayer film (4). To 8), the third step of manufacturing the second semiconductor element while leaving it on, and the step of selectively removing the protective layer (3) with respect to the first semiconductor multilayer film (4 to 8). And an optical integrated device formed by the process 4 and a method of manufacturing the same.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical integrated device formed on a semi-insulating semiconductor substrate and a method for manufacturing the same.

[0002]

2. Description of the Related Art In order to manufacture a device in which semiconductor devices are integrated on a semi-insulating semiconductor substrate, first, a crystal in which semiconductor multilayer films constituting each semiconductor device are laminated is grown. Next, a step of performing mesa processing on the crystal up to the semiconductor substrate and exposing the multilayer films forming the respective elements is performed. After that, it is customary to further perform the steps required to manufacture each device to complete the manufacture of the integrated device.

At this time, the steps required for producing a certain element are not necessary for producing another element, and the semiconductor multilayer film constituting another element is damaged due to the step, and the element's multi-layer film is damaged. Performance deteriorates significantly.

For example, when a device in which a front-illuminated PIN photodiode, which is an optical element, and a field effect transistor, which is an electronic element, are integrated is formed, silicon nitride is used to form the p region of the PIN photodiode by an ion implantation method. A film (SiN) is deposited and the film is used as a mask during ion implantation. Further, in order to increase the light receiving sensitivity of the photodiode, the light receiving portion is provided with SiN, a silicon oxide film (S
iO ₂₎ is deposited an anti-reflection film and the like. Therefore, the surface of the field effect transistor is simultaneously exposed to SiN and SiO ₂
It becomes necessary to remove the film by dry etching.

At this time, it has been reported that the surface of the semiconductor multilayer film constituting the field effect transistor is damaged by dry etching and a metamorphic layer or a defect layer is introduced into the surface. That is, it is as disclosed in the paper "Evaluation of Damage Due to InP Dry Etching" by Morito et al., 1991 Spring Applied Physics Society Academic Lecture, 31p-K-15, Proceedings 3rd Volume, page 1214. .. When only the field effect transistor is manufactured, it is not necessary to perform such a step, and no damage occurs.

As described above, when the manufacturing steps of the respective semiconductor elements constituting the optical integrated element are different from each other, the integration of these elements causes damage, resulting in deterioration of performance of any element. There was a problem.

[0007]

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to solve the above-mentioned problems of the prior art and to provide an optical integrated device having high performance without deterioration of the device performance and a manufacturing method thereof.

[0008]

To achieve the above object, in the present invention, a first semiconductor multilayer film (4 to 4) constituting a first semiconductor element is formed on a semi-insulating semiconductor substrate (9). 8), a protective layer (3) made of one semiconductor layer formed on the first semiconductor multilayer film (4-8), and a protective layer (3) made of one semiconductor layer. The second semiconductor multilayer film (1 to
In the optical integrated device consisting of 2), a protective layer (3) consisting of the one-layer semiconductor is introduced into the first semiconductor multilayer film (4 to 8) in manufacturing the second semiconductor device. The present invention provides an optical integrated device characterized by being a semiconductor layer (3) that protects against damage and can be selectively and easily removed from the first semiconductor multilayer film (4 to 8).

On the semi-insulating semiconductor substrate (26),
The first semiconductor multilayer film (2
5), a second semiconductor multilayer film (22 to 24) forming a second semiconductor element formed on the first semiconductor multilayer film (25), and the second semiconductor multilayer film (22). ~ 2
4) a protective layer (2) made of a semiconductor formed on the
In the optical integrated device including 1), a protective layer (21) composed of the one-layer semiconductor is introduced into the second semiconductor multilayer film (22 to 24) in manufacturing the first semiconductor device. The present invention provides an optical integrated device characterized by being a semiconductor layer (21) that protects against damages and can be selectively and easily removed from the second semiconductor multilayer films (22 to 24).

On the semi-insulating semiconductor substrate (9), a first semiconductor multilayer film (4 to 4) forming a first semiconductor element is formed.
8), a protective layer (3) made of a single semiconductor layer on the first semiconductor multilayer film (4-8), and a second semiconductor element on the protective layer (3). First step (FIG. 1) of growing the semiconductor multi-layered film (1 to 2), the second semiconductor multi-layered film (1-2), and the first semiconductor multi-layered film (4 to 4).
8) a second step (FIG. 2) of exposing the first semiconductor multilayer film (4 to 8) while leaving the protective layer (3) on the first semiconductor; The third step (FIG. 3, FIG. 4, FIG. 5) of manufacturing the second semiconductor element while leaving it on the multilayer film (4 to 8), and the protective layer (3) as the first semiconductor multilayer film. And a fourth step (FIG. 6) of selectively removing (4 to 8).

On the semi-insulating semiconductor substrate (26),
The first semiconductor multilayer film (2
5) and a second semiconductor multilayer film (22 to 2) forming a second semiconductor element on the first semiconductor multilayer film (25).
4) and a first protective layer (21) made of a semiconductor on the second semiconductor multilayer film (22-24).
(FIG. 7), the first semiconductor multilayer film (25), and the second semiconductor multilayer film (22 to 24) on the protective layer (21).
A second step (FIG. 8) of exposing the second semiconductor multilayer film (22 to 24) while leaving the above, and the protective layer (21) on the second semiconductor multilayer film (22 to 24). 1st leaving
Third step of manufacturing the semiconductor element of (FIGS. 9 and 10)
And the protective layer (21) as the second semiconductor multilayer film (22-
24) Fourth step of removing selectively (FIG. 11)
The present invention provides a method for manufacturing an optical integrated device including:

[0012]

According to the above-described means, since the protective layer made of one semiconductor layer is a semiconductor layer for protecting the damage introduced to the semiconductor element, the performance of the optical integrated element can be easily maintained without deterioration of the performance of the semiconductor element. Can be realized.

Further, since the protective layer can be selectively and easily removed, it does not complicate the manufacturing process of the optical integrated device.

[0014]

Embodiments of the present invention will now be described in detail with reference to the drawings.

[0015]

[Embodiment 1] FIGS. 1 to 6 are views for explaining a first embodiment of the present invention.

Here, the semiconductor elements forming the optical integrated element are a PIN photodiode (PIN-PD) and a high electron mobility transistor (HEMT).

The first semiconductor element HEMT has a layer 4,
It consists of 5, 6, 7, and 8. 4 is n ⁺ -InGaAs, 5
Is n ⁺ -InAlAs, 6 is n-InAlAs, 7 is n
-InGaAs, 8 is n-InP. The second semiconductor element, PIN-PD, comprises layers 1, 2, and 3. 1 is n-InP, 2 is n-InGaAs, 3 is n ⁺ -InP
Is.

First, as shown in FIG. 1, on a semi-insulating InP substrate, a semiconductor multi-layer film composed of layers 4, 5, 6, 7, and 8 forming a HEMT, and a layer 1 forming a PIN-PD thereon are formed. A semiconductor multilayer film consisting of 2, 3 is grown.

Next, as shown in FIG. 2, HEMT and PIN
-Expose each PD individually. At this time, the layer 3 is left as a protective layer on the HEMT which is the first semiconductor element.

Then, a silicon nitride film (SiN) is formed on the entire surface in order to form the p region of PIN-PD by the ion implantation method.
Is deposited by plasma CVD. SiN in the region for ion implantation is removed by dry etching, Be ions are implanted using SiN as a mask, and activation annealing is performed to form the p layer 11 (FIG. 3).

Further, as shown in FIG. 4, a silicon oxide film (SiO ₂ ) which is an antireflection film is deposited.

Then, the S deposited on the HEMT
iN and SiO ₂ are removed by dry etching (FIG. 5). At this time, since the layer 3 is provided on the HEMT, the HEMT can be protected from damage due to dry etching.

Finally, the n ⁺ -InP of the protective layer, layer 3, is formed.
Is etched, electrodes are attached, and the manufacturing process is completed. In the above etching process, InP is easily and selectively etched without etching the uppermost n ⁺ -InGaAs (layer 4) constituting the HEMT, and
It would be nice if the surface of T could be exposed (Fig. 6). That is, as the etching method, either wet etching or dry etching can be used. As an etching solution in the case of wet etching, for example, HCl + H ₂ O, HBr + H ₃ PO ₄ ,
HCl + H ₃ PO _4, or can be used HBr + CH ₃ COOH, etc., as the mixed gas when the dry etching, for example, Br _2, Cl _2, or BBr
₃ etc. can be used.

As a result, the performance of the semiconductor device is not deteriorated when the optical integrated device is manufactured, and the inherent performance of the optical integrated device can be easily realized.

The example shown in FIGS. 1 to 6 is the PIN-PD.
This is an example in which n ⁺ -InP of the layer 3 constituting the above can be used as the semiconductor layer for protecting the HEMT, but the protective layer and the constituent layer of the semiconductor element may not necessarily be the same.

[0026]

Second Embodiment FIGS. 7 to 11 are views for explaining a second embodiment of the present invention. FIG. 7 shows a step of forming the layer 25 constituting the MSM-PD, the layers 22 to 24 constituting the HEMT and the protective layer 21 on the semi-insulating GaAs substrate 26, and FIG. 8 shows the HEMT and the MSM-PD exposed respectively. Step of leaving layer 21 as a protective layer on top of FIG. 9, MSM-P
Silicon oxide film (SiO ₂ ) 27 which is an antireflection film of D
FIG. 10 shows the step of depositing SiO ₂ 27 deposited on the HEMT by etching and then removing MSM (Meta
l-Semiconductor-Metal) Photodiode (MSM-P
FIG. 11 shows the step of patterning the electrode 28 of D), and FIG. 11 shows the step of attaching an electrode for HEMT after removing the n-AlGaAs of the layer 21 as a protective layer by etching. The first embodiment is an example of an optical integrated device using an InP semiconductor device, but the present invention is also effective when a GaAs semiconductor device like the second embodiment is used. ..

Here, the semiconductor element forming the optical integrated element is an MSM-PD and a high electron mobility transistor (HE).
MT).

The MSM-PD, which is the first semiconductor element, is composed of the layer 25. 25 is n-GaAs. The HEMT, which is the second semiconductor element, includes layers 22, 23, 24, and 25. 22 is n ⁺ -GaAs, 23 is n ⁺ -AlGa
As and 24 are n-AlGaAs. In this case,
The layer 25 is commonly used for MSM-PD and HEMT.

The n-AlGaAs layer 21 is a semiconductor layer that protects the HEMT which is the second semiconductor element.

Since the layer 21 is provided on the HEMT as in the first embodiment, the silicon oxide film (SiO ₂ ) (layer 27) deposited as the antireflection film of the MSM-PD is removed by dry etching. HEMT from damage when
Can be protected.

Further, n-AlGaA of the layer 21, which is a protective layer, is used.
In the step of etching s (FIG. 11), HEM
The uppermost n ⁺ -GaAs (layer 22) forming T is left unetched and the n-AlG of the layer 21 which is a protective layer is left unetched.
It suffices that the aAs can be easily and selectively etched to expose the surface of the HEMT. That is, as the etching method, either wet etching or dry etching can be used. As an etching solution for wet etching, for example, NH _{4 is used.}
OH + H ₂ O ₂ + H ₂ O, HCl + H ₂ O, or the like can be used, and as the mixed gas in the case of dry etching, for example, CCl ₂ F ₂ or Cl ₂ can be used.

As a result, the performance of the semiconductor device is not deteriorated when the optical integrated device is manufactured, and the inherent performance of the optical integrated device can be easily realized.

In the embodiments of the present invention described above, an example using a protective layer for protecting either the first semiconductor element or the second semiconductor element has been shown. For the first semiconductor element and the second
It is necessary to grow a protective layer on both of the semiconductor devices.

Needless to say, various modifications can be made without departing from the scope of the present invention, such as in the case where the number of semiconductor elements forming the optical integrated element is three or more.

[0035]

As described above, according to the present invention,
The performance of each element as a single unit can be surely obtained by integrating those elements, and the performance originally possessed by the optical integrated element can be easily realized.

[Brief description of drawings]

FIG. 1 is a process diagram illustrating a first embodiment of the present invention, which is a layer (4 to 8) that constitutes a HEMT and a layer (which constitutes a PIN-PD) on a semi-insulating InP substrate (9). 1-3)
FIG.

FIG. 2 shows HEMT and PIN-PD exposed to H
It is process drawing which leaves a layer (3) as a protective layer on EMT.

FIG. 3 shows a layer (1) which is a silicon nitride film (SiN) on the entire surface.
0) is deposited by the plasma CVD method, and then SiN in the region to be ion-implanted is removed by dry etching.
FIG. 5 is a process diagram of forming a p-layer (11) by implanting Be ions with using as a mask.

FIG. 4 is a silicon oxide film (SiO ₂ ) which is an antireflection film.
FIG.

FIG. 5 SiN and SiO ₂ deposited on HEMT
FIG. 7 is a process drawing of removing by dry etching.

FIG. 6 is a process diagram of attaching electrodes after removing n ⁺ -InP of a layer (3) which is a protective layer by etching.

FIG. 7 is a process chart for explaining the second embodiment of the present invention, which is a layer (25) constituting an MSM-PD and a layer (22 to 22) constituting a HEMT on a semi-insulating GaAs substrate (26).
FIG. 24 is a process diagram of forming a protective layer (21) and a protective layer (21).

FIG. 8 shows HEMT and MSM-PD exposed to H
It is process drawing which leaves a layer (21) as a protective layer on EMT.

FIG. 9 is a process drawing of depositing a silicon oxide film (SiO ₂ ) which is an antireflection film of MSM-PD.

FIG. 10 is a view showing an electrode (2) of MSM-PD after removing SiO ₂ deposited on HEMT by dry etching.
FIG. 8 is a process drawing of forming pattern 8).

FIG. 11 is a protective layer (21) of n-AlGaAs.
FIG. 7 is a process diagram of attaching electrodes for HEMT after removing by etching.

[Explanation of symbols]

1 n-InP 2 n-InGaAs 3 n + -InP 4 n + -InGaAs 5 n + -InAlAs 6 n-InAlAs 7 n-InGaAs 8 n-InP 9 semi-insulating InP substrate 10 a silicon nitride film 11 p layer 12, 27 Silicon oxide film 13 p electrode 14 n electrode 15 and 29 source electrode 16 and 30 gate electrode 17 and 31 drain electrode 21 n-AlGaAs 22 n ⁺ -GaAs 23 n ⁺ -AlGaAs 24 n-AlGaAs 25 n-GaAs 26 semi-insulating GaAs substrate 28 MSM photodiode electrode

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification number Internal reference number FI Technical indication location H01L 31/10 (72) Inventor Atsuro Koumae 1-6 Uchiyukicho, Chiyoda-ku, Tokyo Nihon Telegraph and Telephone Co., Ltd.

Claims (4)

[Claims] 1. A first semiconductor multilayer film forming a first semiconductor element on a semi-insulating semiconductor substrate, a semiconductor layer consisting of one layer formed on the first semiconductor multilayer film, and An optical integrated device comprising a second semiconductor multilayer film forming a second semiconductor device formed on a one-layer semiconductor layer, wherein the one-layer semiconductor layer forms the second semiconductor device. An optical integrated device, which is a semiconductor layer which protects damage introduced into the first semiconductor multilayer film and which can be selectively and easily removed with respect to the first semiconductor multilayer film. 2. A first semiconductor multilayer film forming a first semiconductor element and a second semiconductor element formed on the first semiconductor multilayer film are formed on a semi-insulating semiconductor substrate. An optical integrated device comprising a second semiconductor multi-layer film and a one-layer semiconductor layer formed on the second semiconductor multi-layer film, wherein the one-layer semiconductor layer forms the first semiconductor device. In addition, the optical integrated device is a semiconductor layer that protects damage introduced to the second semiconductor multilayer film and that can be easily removed selectively with respect to the second semiconductor multilayer film. 3. A first semiconductor multi-layer film forming a first semiconductor element on a semi-insulating semiconductor substrate, a protective layer made of a semiconductor on the first semiconductor multi-layer film, and the protection layer. A first step of growing a second semiconductor multilayer film forming a second semiconductor element on the layer; a second semiconductor multilayer film; and a protective layer left on the first semiconductor multilayer film. A second step of exposing the first semiconductor multilayer film as it is, and a second step of leaving the protective layer on the first semiconductor multilayer film.
And a fourth step of selectively removing the protective layer with respect to the first semiconductor multilayer film. 4. A first semiconductor multilayer film forming a first semiconductor element on a semi-insulating semiconductor substrate, and a second semiconductor element forming a second semiconductor element on the first semiconductor multilayer film. A first step of growing a semiconductor multilayer film and a protective layer made of a semiconductor on the second semiconductor multilayer film, a first semiconductor multilayer film, and a protective layer on the second semiconductor multilayer film. A second step of exposing the second semiconductor multilayer film while leaving the layer, and a first step of leaving the protective layer on the second semiconductor multilayer film.
And a fourth step of selectively removing the protective layer with respect to the second semiconductor multilayer film.