JPS59129468A - Composite optical semiconductor element - Google Patents

Abstract

PURPOSE:To insulate both a semiconductor light-emitting element and a semiconductor photo-detecting element electrically sufficiently, and to enable unifying so that the junction capacitance is reduced by each forming diodes under reverse bias to several P-N junction of the semiconductor light-emitting element and the semiconductor photo-detecting element. CONSTITUTION:A semiconductor light-emitting element consisting of an LED3-10 with a P-N junction forming a light-emitting section and a photo-detecting element consisting of a photodiode PD3-20 with a P-N junction detecting an optical output from the LED3-10 are unified between opposite each N layer of these two P-N junctions through a low impurity concentration layer 3-30 and a P layer 3-50 each functioning as P-N junctions under reverse bias to these P-N junctions. In such structure, diodes 3-70, 3-71 under reverse bias are each formed to several P-N junction of the LED3-10 and the PD3-20 as shown in an equivalent circuit. Accordingly, the LED3-10 and the PD3-20 are insulated electrically and can be unified, and junction capacitance between both elements can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical field to which the invention pertains] The present invention relates to a composite optical semiconductor device comprising a semiconductor light emitting device and a semiconductor photodetecting device.

[Prior art and its problems] In recent years, with the rapid development of optical communication technology, the integration of optical semiconductor devices has become popular.

In such compounding, conventionally, for example, a light emitting diode (hereinafter abbreviated as LED) (as shown in FIG. 1) has been used.
For example, a photodetector element consisting of a photodiode (hereinafter abbreviated as FD) (1-20) is placed on the semiconductor light emitting element consisting of 1-10) via a low impurity concentration layer (1-:30) serving as a resistive layer. has been devised.

The LED (1-10) is formed of, for example, P-type Ga or A6 on a substrate (i-11) made of, for example, P-type GaA@, through a current confinement layer (1-12) made of, for example, N-type GaAa. A first composition layer (1-+3) is formed.

The structure is as follows. Also, bzD(1-1
One electrode (1-16) of 0) is provided on a part of the upper surface of the second composition layer (1-15) made of N-type GaALA6, and the other electrode (1-17) is P-type GaA
The lower surface of the substrate (1-11) consisting of 6 is divided into two parts.

Next, the FD (1-20) is, for example, N type G4ΩA
N-type layer (1-22) consisting of 8≦2, e.g. P-type Ga
A P-type layer (1-23) of kB is formed.

One @ pole (1-24) of this FD (1-20) is N
It was provided on a part of the upper surface of the type layer (1-22), and the other %L pole (1-25) was formed to obtain ohmic contact with a part of the P-type layer (1-23). It is provided on the upper surface of the diffusion layer forming section (1-26).

From the above structure I-, part of the optical output from L E D (1-1o) is detected by PD (1-20), and another part of the optical output is detected by F D (1-20). The light passes through and enters an optical transmission line provided externally, for example, consisting of an optical fiber (1-40).

PD (1-20) that detected part of the optical output
The electrical output from is used to monitor IIED (1-10).

In the above structure, L w D (1-10) and FD
(1-20) and a low impurity concentration layer formed between (1-20) and (1-20).
3+) ) is I, E D (1-10) and F D
(1-2 (1) is electrically insulated and L w D (1-
10) is prevented from leaking into the FD (1-20).

Such a low impurity 1IJ4°l@(]-30) has conventionally been formed as an insulating layer by ion implantation, as disclosed, for example, in Japanese Patent Application Laid-Open No. 55-145380.

This ion implantation (when forming the second insulating layer, high-purity If
With the ion implantation technology for Sl, the reduction in impurity concentration has reached 1×10/- or less.
Converting to specific resistance q, it is possible to form a high resistance layer on the Ω· side of several tens of Ω.

However, ion implantation of, for example, 9-element or oxygen ions using the above-mentioned C2 into a composition layer of, for example, GaAB, which is mainly used in LFiD or structured semiconductor lasers,
Its fine molecular beam epitaxial growth (MBB: M
o1ular beam epitaxy) and metal organic pyrolysis vapor phase deposition (MOOVD: Metal
oryanicOhemical Vapor Dep
Even if techniques such as ositlon) are used, the limit is to reduce the impurity concentration to IX1414/c#l to IX10/cl.

In other words, when converted to specific resistance, it becomes several 100.1, which is FD (
When the diameter of 1-20) is, for example, 100 μm, and the thickness of the impurity concentration layer (1-30) is, for example, 10 μm,
The resistance due to this low impurity concentration layer (1-30) is several hundred
The resistance is as low as Ω.

Therefore, in the above structure C2, the LED and FD in the equivalent circuit shown in FIG.
0), and it is difficult to electrically insulate the LED and FD to a certain extent.

As a result, when LKD and FD are integrally formed, the LED m
Part of the υ production m'l IAt flowed into the PD, making it difficult to detect the true monitor 111 flow on the FD.

Furthermore, the thickness of the layer formed by conventional ion implantation is about 1 μm, and the resulting capacitance is large due to this thin film. Junction capacitance between the two has arisen as a new problem.

[Object of the invention] This invention was made in consideration of the above drawbacks,
The purpose of this is to sufficiently electrically insulate the LED and FD and reduce junction capacitance (by forming them in one piece, we can create a composite optical semiconductor element that can detect the true monitor current with the FD). It is to provide.

[Summary of the Invention] The present invention provides a semiconductor light emitting device having a tenth P-N junction, and a cell 2 for detecting light output from the first P-N junction.
A semiconductor photodetecting element having a P-N junction of N junction i
A composite optical semiconductor element is obtained which is formed integrally with two pairs of pfWj, a structure N layer, or a P-N junction layer, each of which forms a reverse bias PN junction, through a laminated structure.

[Effects of the invention] This invention enables signal separation and reduces junction capacitance by electrically insulating the LED and PD by 20 minutes.
It is possible to obtain a composite optical semiconductor device which can easily be formed into two integrated devices and which can detect a true monitor current using 52 PDs.

[Embodiment of the Invention] A first embodiment of the invention will be explained with reference to Figures 3 and 4 of Ki.

For example, a T
Jl! ! For example, a P-N junction having a semiconductor unitary light emitting device consisting of D (a-IO) and a second P-N junction for detecting the light output from this L B D (3-10) by a light receiving section.
D(3-20), and a low impurity concentration layer (
a-30) and one layer (3-50
) and are integrally formed.

The LED (3-]0) has an impurity concentration of 1×1, for example.
018/ctl with a thickness of 100 to 200 μm
On a substrate (3-11) made of m aahB, for example, a current confinement layer (3-12) made of an N-type layer aA6 with an impurity concentration of 1×10/crI and a thickness of 4 to 5 μm is formed. For example, a P-type Ga1-metal A8 with an impurity concentration of lXl0/c- and a thickness of 4 to 5 μm (χ=0.3
A first composition layer (3-13) having a composition of 0.4 to 0.4) is formed.

Further, on this first composition layer (3-13), for example, N-type GaA with an impurity concentration of 1 xio/m and a thickness of 1 μm is formed.
For example, N with an impurity concentration of I x 1018/lr4 and a thickness of 5 μm is passed through the active layer (3-14) made of B.
Layer Gal −zAJLzAa (χ=0.3 to 0.4
) A second composition layer (3-15) is formed.

Incidentally, the current confinement layer (3-12) is partially formed in order to improve l''-current flow and obtain high luminous efficiency.

Also, one electrode (3-16) of the LED (3-10) with
) is provided on a part of the upper surface of the second composition layer (3-15), and the other electrode (3-17) is provided on the substrate (3-1
1) The lower surface l is bifurcated.

Next C1 the FD (3-20) has an impurity concentration of 1, for example.
N-type Gal-gAJ with Xl018/d and a thickness of 1 μm
N-type layer (3-
22) On top, a P-type layer, l -ddzAB (z
= 0.3 to 0.4) is formed and configured.

One electrode (3-24) of this FD (3-20) is N
The other electrode (3-25) is provided on a part of the upper surface of the type layer (3-22), and the other electrode (3-25) is formed to obtain an ohmic contact with a part of the P-type layer (3-23), e.g. P+
The upper surface C of the diffusion layer (3-26) made of GaA3 type is bifurcated.

In the above structure, I, BD (3-1
0) N-type layer (3-15) and this (-opposed FD (3
-20) PP type layer 3 between each layer of N type layer (3-22)
-50), the LED (3-10) and FD (3-20) can be
A reverse-biased diode (
3-70 and 3-71) will be formed.

That is, if the potential of the N-type layer (3-15) of LEn (3-river) determined by the connection with the external circuit is higher than the potential of the N-type layer (3-22) of FD (3-20), I, F! D
(3-Iff), the N-type layer (3-22) and the P-type layer (,
1-50) will act as a reverse-biased diode (3-70).If the above potential relationship is reversed, %FD(320)
and P type layer (3-50).
The -N junction functions as a reverse bias diode (3-71).

On the other hand, the resistive low impurity concentration layer (3-30) interposed together with the P-type layer (3-50) is formed using molecular beam epitaxial growth or metal-organic decomposition vapor phase epitaxy.
The thickness can be approximately 0 μm, and the LBD (3-10
) and F D (3-2(1)) can be effectively prevented.

As described above, according to the present invention, L
E D (3-In) and FD (3-20) can be electrically insulated and integrally formed, and LED (3-In) can be electrically insulated and integrated.
10) and F D (3-2 (3)) can be reduced to i1&.

Next I: A second embodiment that further improves the first embodiment of the invention.
An embodiment will be described with reference to FIG.

I, ED (3-10) and P-type layer (3-56)
, composition with low impurity concentration r@(3-30), impurity concentration 9
The layer thickness etc. are the same as in the first embodiment described above.

This second embodiment includes a PP type layer 3-50) and a low impurity concentration layer (3-:
LED on the FD (5-20) formed by interposing
A space (5-60) for passing the light output from (3-10) to the outside is provided.

The p D (5-2t)) is, for example, if the impurity knitting degree is I
N-type GaAB with X 1018/C- and a thickness of 1 μm
For example, an impurity is placed on the N-type layer (5-22) consisting of
A P-type layer (5-23) made of P-type GaA3 with a thickness of 3 μm and a thickness of 1X10/l is formed.

That is, the active layer (3-14) of L E D (3-10)
The light output from the FD (5-20) is received by the FD (5-20), and since its center is hollowed out, a portion of the light is output to the outside through the light passage section (5-60). into the optical fiber (1-4t)).

Therefore, with the above structure, LF! D(
3-10) and F D (5-2 (1)) can be integrally formed to electrically insulate and reduce junction capacitance, and the area of the forming surface of Amata P D (5-20) can be By reducing the junction capacitance of FD (5-20), the sensitivity can be increased.

In addition, ■, FD (3-10) optical fiber (1-40
) and the light output surface to the l151-plane (two provided F D
(5-20), the optical fiber (
Since the optical output to 1-4 (J) and the optical output to FD (3-20) are obtained as fairly similar waveforms without being subjected to different distortions, monitoring by p D (3-2!0) It is possible to increase the degree of treetopness.

In addition, when the FD (3-20) is a transmission type as in the first embodiment, the composition of B and P D (3-20) is changed in order to obtain a predetermined optical output to the optical fiber (1-413). , it is necessary to set the impurity concentration layer thickness etc. extremely precisely.
According to the above hollowed-out structure C-, M1 of pD(3-20)
Conditions such as layer thickness, impurity concentration, and layer thickness can be relaxed to 112 degrees.

Note that each of the opposing phases between the LED and the FD is N layers in the first and second embodiments described above, but when each of the opposing phases is two layers, the first and second embodiments have N layers. It is clear that it is sufficient to interpose an N layer for a 1-% reverse bias diode, contrary to the example.

Furthermore, a third embodiment of the present invention will be described with reference to FIGS. 6 and 7.

L E D (3-10), p-type layer I! (3-50
) and the low impurity temperature layer ('3-30), the impurity concentration layer thickness, etc. are the same as in the tenth embodiment described above.

This third example uses LED ('3-10) and PD (
6-20) and the lamination +1b on the LED (3-10)
+- P type layer ('a-50) + N type layer (6-70) and low impurity temperature layer (3-30) are interposed and formed integrally.

Here is the previous ir! ' F D (6-20) is, for example, P with an impurity concentration of 1 x 1018/d and a thickness of 1 layer m.
For example, on the P-type layer (6-22) made of type layer aA6, the impurity concentration is I x 1018/cr4 and the thickness is 3μ.
m N-type layer a N-type layer (6-2: D is formed) consisting of AB.

￥P, one electrode (6-24) of F D (6-20)
)ld, provided on a part of the top surface of the P-type layer (6-22), and the other electrode (6-25) provided on a part of the top surface of the N-type layer (6-23) .

When providing the other electrode (6-25) on this N-type layer (6-23), for example, Au-E11 alloy is heated at 400°C to 50°C.
It is formed by heat treatment at about 00°C.

That is, in this example, the N-type layer (
3-15) and the P-type layer (6-22) of the FD (6-20) facing this, there is a P-N junction of the LED (3-10) and the P-N junction of the FD (6-20). ) second P-N of
A P-type layer (3-50) and an N-type layer (6-70) that form a reverse-biased P-N junction with respect to the junction 11 7
5; It has a structure in which it is formed.

Therefore, the N-type layer (3
-45) and P-type layer (6-22) of PD (6-211)
Regardless of the potential relationship C2, the equivalent circuit shown in FIG.
6-20) Reverse biased diodes (
7-70 and 7-71) are formed to form a sheet resistance layer.

As mentioned above, the LED and FD that are integrally formed with this structure
Even if the opposing layers are P-type and N-type, it is possible to electrically insulate TJ Fi D (3-10) and FD (3-20) and reduce the junction capacitance. .

Next
An example of this will be described with reference to FIG.

L E D (3-10), pff, H1il+
The compositions of the (3-50), NmN (6-70) and low impurity concentration layers (3-:30), the thickness of one layer of impurity concentration, etc. are the same as in the third embodiment described above.

This fourth embodiment has a P-type layer (3-5(1)) and an N-type layer (6-70) stacked on LKD (3-10).
) and a low impurity layer (3-:30), the light output from the LED (3-10) is transferred to the outside. A light passage section (5-60) is provided to allow the light to pass through.

For example, the P D (8-20) has an impurity concentration of 1×
1018/cd, the P-type layer (8-22) made of P-type GaAB with a thickness of 1 μm has an impurity concentration of I, for example.
X 1018/cJ, N-type layer with a thickness of 3 μm a A
An N-type layer (8-2:3) made of B is formed.

It is also integrally formed to reduce the junction capacitance.
-20) High sensitivity can be achieved by reducing the junction capacitance.

Furthermore, optical output to fiber (1-4,0) and PD (8
-21)) It is possible to obtain waveforms that are quite similar to the output, and conditions such as the composition of the FD (8-20), the impurity concentration, and the thickness of the 9-layer layer can be moderately adjusted.

Note that each opposing layer between LID and FD is the same as the third layer described above.
In the case of the fourth embodiment, the LED side is the N layer and the ED
If the LED side is the P layer and the FD side is the N layer, it is sufficient to interpose a P-N junction layer whose lamination relationship is opposite to that of the third and fourth embodiments described above. is clear.

Furthermore, in the first to fourth embodiments C described above, the LED and F
It is clear that the f# layer relationship between the low impurity concentration layer interposed between D and the P layer, N layer, or PN junction layer may be reversed.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a conventional structure in which an LED and FD are combined, FIG. 2 is an equivalent circuit diagram of the conventional structure shown in FIG. 1, and FIG. 3 is a first embodiment of the present invention. 4 is an equivalent circuit diagram of the composite optical semiconductor device shown in FIG. 3C, and FIG. 5 is a cross-sectional view of the composite optical semiconductor device shown in FIG. 6 is a cross-sectional view of a composite optical semiconductor device showing a third embodiment of the present invention, and FIG. 7 is a cross-sectional view of a composite optical semiconductor device showing a third embodiment of the present invention. This is an equivalent circuit diagram, and FIG. 8 is a sectional view of a composite optical semiconductor device showing a fourth embodiment which is a further improvement of the third embodiment shown in FIG. 1-40...Optical fiber 3-10...LFiD
3-11... Substrate 3-12... Current confinement layer 3-13... First composition 78 3-14... Active layer 3-15... Second composition layer 3-16. 3-17...LED electrode 3-20. 5
-20. 6-20. 8-20...ED3-22.
5-22.6-23.8-23...N-type layer 3- of FD
23.5-23.6-22.8-22...P-type layer 3-24 of FD. 3-25. 5-24. 5-256-
24.6-25.8-24.8-25... FD electrode 3-26.5-26.6-26.8-26... Diffusion layer 3-: 30... Low impurity concentration layer 3-50...P type layer 3-70.3-71.7-70.7-71...Reverse bias diode 5-60...Light passing section 6-70...N type layer substitute Person: Patent Attorney Noriyuki Chika and 1 other Figure 8 Procedural Amendment (Voluntary) 1. Indication of the case, Patent Application No. 3360 of 1982. 2. Name of the invention, composite optical semiconductor device. 3. Name of the person making the amendment. Related: Patent originator (307) Tokyo Shibaura Electric Co., Ltd. 4, agent 〒io. 1-1-6 Uchisaiwai-cho, Chiyoda-ku, Tokyo Detailed description of the invention in the specification column 6, Contents of amendment (1) Specification page 8 line 13 t7) "GaAs J
[GaAs or Ga1-xAffl, As (x =
0.05~0.1)-J. (2) “Oal” on page 9, line 6 to line 7 of the specification
x, fiJ xAs (x = 0.3 to 0.4)J
[Ga1, AA! , As (x=0.3 to 0.4
) or GaAs J. (3) [GaAs J] on page 14, line 3 of the specification
aAs or Ga 1. AidxAs (x = 0.3
~0.4) Corrected as J. that's all

Claims (1)

[Scope of Claims] (1) A semiconductor light-emitting element having a first PN junction forming a light-emitting part, and a second light-receiving part forming a light-receiving part that receives part of the light output from the semiconductor light-emitting element. In a composite optical semiconductor cable C1 formed by laminating a semiconductor photodetecting element having a P-N junction via a resistive layer, an interlayer 1'' between the first and second P-N junctions faces each other. l-, a P layer or an N layer or a P-N junction layer is interposed between the first and 20th P-N junction groups to form a reverse-biased P-N junction, respectively. Composite optical semiconductor device 0
(2) The composite optical semiconductor device according to claim 1, wherein the semiconductor detection device transmits another part of the optical output from the semiconductor light emitting device to the outside. (8) The semiconductor light detecting element has a light passage section in the center 62 through which the other part of the light output from the semiconductor light emitting element passes to the outside. Waste metal optical semiconductor device. (4) The composite optical semiconductor device according to claim 1, wherein the resistive layer has a thickness of 5 to 20 μm.