JPH01120012A - Compound semiconductor device - Google Patents

Abstract

PURPOSE:To form a III-V compound semiconductor of good quality on a silicon sub strate so that the integration of optical circuits and electronic circuits, and so forth are enabled, by employing a specific structure in which an InxGa1-xP layer is grown on the silicon substrate with the parts of the component x thereof being progressively increased, and the III-V compound semiconductor layers are formed on the InxGa1-xP layer in order to form a device section therein. CONSTITUTION:A first semiconductor layer 2 of InxGa1-xP semiconductor is formed on a silicon substrate 1 with the parts of the component x being progressively increased from the x=0, approximately. Second semiconductor layers 3-5 of a III-V compound semiconductor are then formed on the first semiconductor layer 2, respectively, in order to form a semiconductor device section therein. For example, an n type InxGax-1P layer 2, which has such a graded composition in that the parts of the component x is gradually increased from x=0, approximately, at the lower surface in contact with the silicon substrate 1 from the lower surface to the upper surface, is first pro vided on the silicon substrate 1. Then, an n type AlyGazIn(1-y-z)P layer 3, an active layer 4 of AlyGazIn(1-y-z) layer or InxGa1-xP layer, a p type AlyGazIn(1-y-z)P layer 5, n and p type buried layers 6, 7 of AlyGazIn(1-y-z)P layer, and n and p type electrode layers 8, 9 are provided, respectively. Thereby a buried type laser is produced.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to compound semiconductor devices, and in particular to semiconductor FIC devices.
Electronic devices such as T-shirts and diodes, or optical devices such as semiconductor lasers, light-receiving elements, and optical waveguides are intended to be constructed on the 81 substrate.

2. Description of the Related Art Conventional semiconductor electronic devices are constructed on Si single crystal substrates, and have now developed to the point where high-density, highly integrated ultra-LSIs can be realized. In addition, compound semiconductors, mainly GΔm, which are expected to be used for ultra-high-speed electronic devices, have many crystal defects and process technology has not reached the level of Si, so high-density integration is still difficult. We have not yet reached the point where we can supply large quantities of high-quality devices.

On the other hand, optical devices such as semiconductor lasers require a direct transition type semiconductor, and Si cannot be used because it is an indirect transition type semiconductor. Compound semiconductors such as GaAg and InP are commonly used, but as with electronic devices, sufficiently high quality crystal substrates have not been obtained.

Recently, the advantages of Si's high quality, safety, and large area, and GaAs'
GaAs layers have been epitaxially grown on Si in order to combine the characteristics of high mobility and direct transition with Si.

Problems to be Solved by the Invention However, although epitaxial growth has become possible, it has many problems such as cracking, peeling, and defects in the grown layer, and has not been put into practical use.

Therefore, the present invention aims to form a high quality m-v group compound semiconductor on Si, and further aims to realize the features of optical devices such as semiconductor lasers and Si as an integrated device.

Means for Solving the Problems The present invention provides a method for obtaining a high-quality ■-Ma group compound semiconductor layer on a Si substrate.
The crystallinity is improved by interposing a P layer. In particular, InGaAsP or AlGaI
The nP compound semiconductor is promising as a visible light emitting material, and is grown by gradually increasing the number of InxGa1-XP layers on the Si substrate. Alternatively, a layer lattice of InGaP with different compositions is grown. A layer of InGaAsP or InGaAsP is grown thereon.

This grown layer is used to construct a device.

Devices include optical circuits such as semiconductor lasers, light-receiving elements, and optical waveguides, or electric ICs.Furthermore, optical circuits are formed in the m-v group compound semiconductor growth layer, and electronic circuits are formed in the Si substrate. is also possible.

Function When growing a single crystal thin film on a single crystal, factors such as surface condition, difference in thermal expansion coefficient, lattice matching, and crystal lattice shape play a large role. In particular, when the crystal lattice types match, the difference in lattice constants greatly influences epitaxial growth.
It has a large effect on crystallinity. Therefore, in this patent, InzGa 1-z which is very close to the lattice constant of the Si substrate
The initial growth composition is P (X Z O), and the In composition is gradually increased until the composition has a desired lattice constant, and on top of that, a high-quality composition film with a device configuration can be obtained. It is something that we have. Furthermore, it is generally difficult to form short wavelength light emitting elements on Si, and GaA
Even with s/Si crystals, it has not yet been possible to obtain a highly efficient light emitting device. In this patent, GaAs/
InGaAsP has a much smaller lattice mismatch than Si and is required for short wave light emitting devices.

This has the effect of enabling crystal growth of A/GaInP and the like.

Embodiments 1-2 FIG. 2 shows the implementation of the present invention. Figure 1 shows Si
FIG. 2 shows a perspective view of a laser formed on a substrate. FIG. 2 shows a cross-sectional structure including the active region. 1 is an n-8i substrate, 2 is an n-InzGa 1-xP layer, and the composition X is S.
The i-substrate has a graded composition that gradually increases from near x=0. 3 is n-people/yGazIn(1-y
-z) P (bandgap IC+) layer, and 4 is the active layer Mu#yGaz In (+-y-z)P(
2) In the bandgap layer, E + > E 2 or an InzGa 1-xp layer. 5 is P-A, 5
yG! LzIn(1-y-2)P layer (band gap E
3) and E3) is 42. 6°A is an n-type and p-type buried layer, which is a 5yGazIn1-yzP layer. 8 and 9 are n-type and p-type electrode layers.

This buried type laser is recombined in the active layer 4 by passing a current between the layers 8 and 9, and the light is confined in the layers 3, 5, and 6. By changing the lattice constant of the InzGal-xP layer on Si in a graded manner, the lattice constant can be made to match that of the cladding layer 3 and the active layer 4, forming a βGaInP layer with good crystallinity and few defects. be able to.

Figure 3 shows human 1P-GULP-InP and InP-Ga.
The relationship between P-GaAs-InAs composition and band gap is illustrated. Straight lines H-B-C indicate the same composition of lattice constants. For example, the composition of 3.5 indicates a mermaid, 4 indicates the composition of point B or point 0, and 6 and 7 indicate the composition of point H.

Similarly, good crystal growth can be achieved with InGaAsP systems as well. C-G is still an equilattice constant line, but
The active region 3 in FIGS. 1 and 2 has a C point composition of 3,
InGaP, G point, InGaAsP D point, or B point composition of Mu1GalnP can be used for the cladding and buried layer of Nos. 5 and 6.7.

At this time, it goes without saying that the layers 3, 5, and 6.7 do not need to have the same composition, but only need to have a band gap larger than that of the active region 3. Therefore, in the InGaAsP system, three cladding layers are not necessarily required. With this configuration, a short wavelength (visible light) laser, which has been difficult to obtain in the past, can be constructed on an eight-layer substrate. Further, although this embodiment shows the case of a laser, a surface-emitting or edge-emitting LED may also be used.

The above describes the two layers in Figure 1 as I nzGa 1-3C
We have described the case of a graded layer in which X of the P layer is increased sequentially, but this second layer is made of InGaP (
A similar effect can be found with a superlattice containing a layer (G point). The two layers in Figure 1 are GaP or InGaP (F point composition) and InGaP (B point composition).
10 to 20 layers of approximately 6oλ each are alternately formed on the i-substrate.

By forming 4th and 6th layers on this lattice film to form an active region and a cladding layer, it becomes possible to construct the laser shown in FIG. 1 in the same manner as described above.

By forming graded layers of InxGa and -xP on Si, we can create not only InGaAsP (, GaA
Is SP Sb etc. also lattice matched? It is possible to grow the material, and it is also possible to form light-receiving elements and electronic circuits. FIG. 4 shows an example of a configuration of a light receiving element.

A graded layer 2 of n-InGaP is formed on the Si base 1, and a graded layer 2 of n-InGaP or n-InGaP is formed on top of it.
- A layer 10 of GaAsSbP is formed. Furthermore, a P-InGBAsP layer 11 with a large band gap is formed. By forming the electrode layers 12 and 13i, a single heterostructure PN or PIN type light receiving element is obtained.

Furthermore, by growing such a ■-■ group compound semiconductor on Si, it is possible to completely form a P# Si layer by diffusion and use it as a light-receiving part of a light-receiving element. It can also be used as a monitor light receiving section. Electronic XCs such as laser, I, and ED drive circuits, control circuits, or signal processing circuits can be formed in the Si layer, and optical circuits mainly for optical devices can be formed in the m-Ma semiconductor layer. However, it becomes possible to create an optical integrated circuit that combines the features of both.

For the growth of the ■-Ma group on this Si, MO-C is an example.
The VD method is used. For the formation of the InGaP layer, (CH535In, (CH5)5Ga) was used as the source material.
Or (C2Hs)5In, (C2Hs)5
PH4 or the like is used as a source of P in an organic metal such as Ga.

700 "Q ~ 900' (:: Place the substrate Si on
Grow an InGaP layer. At this time (CI(5)3G
'By gradually increasing the amount of L, high-quality InGaP
A layer is formed. On top of this, high-quality -M group mixed crystals for various devices are grown.

Effects of the Invention As described above, according to the present invention, the following effects can be obtained.

(1) By forming a graded InGaP layer on a Si substrate, a high-quality 1-V group film can be obtained.

(2) It is possible to integrate optical circuits and electronic circuits.

(3) Large area is possible.

(4) It is inexpensive.

It has the following effects.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of a laser structure according to an embodiment of the present invention, and FIG.
The figure is a cross-sectional view of the laser in Figure 1, and Figure 3 is a state diagram of InGaAgP, A, and jGaInP that make up the laser.
FIG. 4 is a sectional view of a light receiving element according to another embodiment of the present invention. 1-...-n-5i board, 2...-n-nx
GaI-xp. 3...n- people%GazIn (+ -y -z)
P, 4...active layer, 6...P-AdGa
InP layer.

Claims (3)

[Claims] (1) A first semiconductor layer in which the composition X of an In_XGa_1_-_xP semiconductor is gradually increased from around X=0 is formed on a Si substrate, and on this first semiconductor layer,
A compound semiconductor device comprising forming a second semiconductor layer of a group III-V compound semiconductor and configuring a semiconductor device in the second semiconductor layer. (2) The semiconductor device configured in the second semiconductor layer is I
The compound semiconductor device according to claim 1, which is a semiconductor laser having an active region having an nGaAsP or AlGaInP layer as a light emitting region. (3) In_XGa_1_ with different compositions X on Si substrate
2. The compound semiconductor device according to claim 1, wherein the III-V compound semiconductor device is constructed on a superlattice film in which -_XP semiconductors are grown alternately in multiple stages.