JPS5885583A - Manufacture of semiconductor laser - Google Patents

Abstract

PURPOSE:To form a high specific resistance layer having preferable boundary surface and surface state and preferable electric characteristics by converting a semiconductor layer into a high specific resistance layer by ion implantation. CONSTITUTION:The first clad layer 2, n or p type or undoped active layer 3, the second clad layer 4 and a cap layer 5 are formed on a substrate 1, and a high specific resistance layer 6 is formed by oxygen ion implantation around the layer 5. A layer 7 for forming a circuit element forming region is formed on the layer 6, a source electrode 8, a gate electrode 9, a drain electrode 10, an insulating film 14 and metal electrodes 12, 13 are formed, thereby forming a field effect transistor. The respectively semiconductor layers of the semiconductor laser are formed of at least three types of elements of a group consisting of In, Ga Al, As, P and Sb.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a semiconductor laser device, and more particularly, the present invention relates to a method for manufacturing a semiconductor laser device, and more particularly, it relates to a semiconductor laser device having an integrated circuit device and an integrated circuit device for modulating a current flowing through a light emitting region. The present invention relates to a method for manufacturing a laser device.

Proposals have been made to emit light and introduce it into glass fibers, etc., to apply it to optical communications.

Conventionally, in this type of device, a high resistivity or conductive semiconductor layer has been formed by a liquid phase growth method, a thermal diffusion method, or the like. However, in the liquid phase growth method described above, it is difficult to accurately control the doping amount, and it is difficult to form a stable high resistivity layer in its entirety.

In addition, selective liquid phase growth has the disadvantage that the semiconductor layer is formed with mutual effects such as strain on other semiconductor layers, resulting in extremely electrical deterioration of the completed device. did.

An object of the present invention is to provide a fc semiconductor laser device suitable for use in functional device circuits, etc., with a simple configuration and without the above-mentioned drawbacks.
An object of the present invention is to provide a method for manufacturing a vR-compliant semiconductor laser device.

The structure of the present invention for achieving the above object includes a step of further forming a single layer or a multilayer semiconductor layer on an active layer provided on a semiconductor substrate, and adding oxygen or A/element into the layer. The method includes the steps of selectively implanting ions, and providing a high resistivity layer formed by the ion implantation or a circuit element formation region on the layer.

In the present invention, by converting a semiconductor layer into a high resistivity layer by ion implantation as described above, a high resistivity layer having good field-2 and surface conditions and good electrical characteristics is formed. In other words, unlike methods such as liquid phase growth, which are formed by sequentially stacking new layers, existing semiconductor layers are gradually converted into a high resistivity layer, making it possible to easily obtain stable layers. . By drawing the wire, an element forming region will be formed in a later step. Since this process is carried out in a high temperature atmosphere of 800 to 1000'C, it is used in conjunction with a heat treatment process after substantial ion implantation, and has the advantage of simplifying the process. Implant energy is 800-1500KeV and 10”
~10”cm-2 is implanted.

This implantation energy is several times higher than that in the case where all conductivity type impurities are doped. If it is less than 8o, 0KeV, a sufficiently high resistivity layer cannot be obtained, and if it is less than 15001 (e
If it exceeds V, it is not preferable because it may even cause defects in the semiconductor 1-. The implantation depth varies depending on the size of the desired element, but is usually 1 to 5 μm, a depth that does not reach the active layer.
It is also important to form the layer deeper than the cap layer.

Further, it is necessary to perform the implantation selectively in advance through a predetermined mask to avoid the laser emission region. As mentioned above, since it is implanted with high energy, it is possible to easily form a high resistivity layer to a deep depth. Further, the peak concentration of the implanted atoms is 0.5 to 0.6 μm from the surface. This: t'Ll-1: has a region with a higher insulating effect inside a predetermined semiconductor layer, making the high resistivity layer even more effective, and increasing the surface and deeper regions within the semiconductor layer. It also has the effect of preventing crystal damage caused by acid doping. These implantation techniques are basically the same as those used to form ordinary silicon semiconductor devices, and do not require any new special accessory equipment, so they are extremely simple and easy to use for electrical implantation. A semiconductor laser with good characteristics can be provided.

In this way, ion implantation maintains the implanted semiconductor layer in an extremely stable crystalline manner without destroying it, forming a high resistivity layer with fc intact, so it is possible to implant other semiconductor elements into this implanted layer. The full OJ' capability for forming the element formation region is achieved by the following steps. In addition, this implanted layer has a stable surface, so the crystal consistency is good, and even if another semiconductor layer is formed on this layer, this semiconductor layer will have perfect crystallinity. A semiconductor layer can be used as an element formation region.

As mentioned above, by forming a high resistivity layer that is very close to an insulator in the semiconductor layer, the light emitting element part such as a laser diode is separated from the circuit part, and the current flows to a specific region. It has a concentrated current confinement effect in the laser element, promotes efficiency of operating current, and
The laser element and the active circuit are insulated and separated. This insulation isolation is formed by implanting oxygen ions or the like into a compound semiconductor layer or the like in which an element different from a conductivity type impurity is implanted into a semiconductor layer by ion implantation. As the ion source, in addition to the above-mentioned oxygen and A/2, any ion source that does not change after implantation may be used depending on the purpose. It is important that the resistivity does not become low due to heat treatment after implantation. In this sense, oxygen, A/, etc. are preferred. The high resistivity layer may have a depth that is shallower than the active layer of the laser and deeper than the cladding layer, although it is sufficient that the laser element portion and the circuit element portion are separated as described above. In this way, the operating current can be used effectively without spreading before it reaches the active layer, and the effect of narrowing the current can be more effectively used without the crystallinity decreasing due to implantation reaching the active layer. Ru.

-J7C1 semiconductor materials include u, In, Ga,
AI! It is important that the constituent elements be at least three of the group consisting of , AsP, and sb. These are Hete diagrams. A cross-sectional view taken in a plane perpendicular to the traveling direction of laser light is shown.

An active layer 3 with a thickness of 0.3) is formed on the n-Ga A S substrate 1 by a known liquid phase growth technique, and a layer 3 with a thickness of 1 to 3 μm is formed on the layer 3.
p-(ja, -, A7j, As (0,2≦Z≦
0.7) and a second layer 4 with a thickness of 0.
．． A cap layer 5 of p-GaAs having a thickness of 1 to 0.7 μm is formed. A high resistivity layer 6 is formed around this cap layer 5 by, for example, oxygen ion implantation.

- indicates the existing emission area of the laser; In order to control the transverse mode of the laser, a recess (groove) having an inverted trapezoidal cross section may be provided in advance in the substrate 1 as shown in the figure. A circuit assembly forming region is formed on the high resistivity layer 6 by a method described later in parallel to the laser element region.
The GaAs layer 7 is not provided. On or within the region 7, a C, 1 circuit functional element is formed by known manufacturing means. For example, as shown in the figure, the source electrode 8,
A field effect transistor is constructed by providing a gate electrode 9, a drain electrode 10, an insulating film 14, and metal electrodes 12 and 13. FIG. 2 is a schematic top view of FIG. 1 above. The metal wiring 12 is the electrode part 1 of the laser.
1 is connected. On the other hand, the source electrode 8 of the FET
It is connected to the. The gate electrode 9 is the drain′
The electrode 13 connecting the electrode 11 to the pole 10 is divided and the intermediate portion is connected to a gate bonding pad 16. The form and shape of these electrodes 12, 13 and 16 can be changed as appropriate depending on the circuit element and purpose of use. Next, the manufacturing method of the present invention will be described.

Each semiconductor Jf12, 3.4 and 5Te of semiconductor non-laser
It was obtained by adjusting the amount to 0.5 mg.

In addition, the active layer 3 contains 6 g of G'a and GaAs ((400
mg, and A/ is 2 mg, and the cladding layer 4 is made of Gaf.
6g, 400mg of GaAs, AI! 10mg%
Then, Zn is added to 30 mg, and the cap layer 5 is made of Cx a f 5 g , (J a A S f
400” L and Zn f 30 mg VC
It can be obtained by adjusting the a.

As shown in Figure 3, striped grooves (depth 0.5-5
μm) n-type GaAs with 18'i #! - Full growth of semiconductor layers 2 to 5 as described above on a conductor substrate. The thickness of each layer is as described above.

An ion implantation mask 17 is formed in a band shape using photoresist or the like above the region where laser oscillation is to be performed (this corresponds to the above-mentioned groove portion).

As shown in FIG. 4, through the ion implantation mask 17,
00 KeV, depth 0.5-2 μm te oxygen io/21
is implanted to form a high resistivity layer 6. Next, as shown in FIG. 5, after removing the mask 17i, the n-GaAs layer 7 is removed.
f, thickness 0.2 to 5 μm manufactured by Q phase growth method. Using an ordinary chemical etching method, the n-GaAs layer 7 is left only in the portion where 1='ET is to be formed. The p-GaAs layer 5 is exposed on the region corresponding to the laser element part (
Figure 6). A thickness of O15/! is applied to the entire surface of the semiconductor substrate thus prepared. 7rrl) SiO□ film 14f: Formed by CVD method, and 5
Selectively remove the in2 film. FIG. 7 shows this state. Au-Ge-Ni is deposited on the removed portion, patterned into a predetermined shape, and then alloyed to form the electrode 8,
form 10. Next, as shown in FIG. 1, the Sin! corresponding to the laser electrode section is formed. The film is opened and the laser electrode part and gate electrode part K T i , Cr, Au
are laminated and vapor-deposited to form a predetermined metal pattern. After polishing the back side of the substrate crystal and making it thin to about 100 μm,
After Au-8n is evaporated with the n side as the pole 18, the elements are separated and bonded. In this way, a semiconductor laser device equipped with an active circuit is formed. Figure 1 shows this completed drawing.

will be explained using FIGS. 8 and 9. Figure 8 Deke Laser Robbery 1
800 to 1.500 when implanting oxygen ions after artificial creation
KeVO is implanted with high energy, and as shown in the figure, the oxygen concentration is relatively low at the surface, and the oxygen concentration is 0.5 to 0.6μ from the surface.
A complete pull file with a peak at m is formed. At this time, the oxygen concentration near the peak ゛;T is sufficient for the laser.
E'1'' is completely separated, and the oxygen concentration near the surface is sufficiently low that the properties of 1!'' ET produced here are not impaired. Furthermore, on top of this (11) as shown in Figure 9 (if Si or Se is Si, 75 to 10 QKeV, 5 x 10" to 5
012cm-2S e is 250-300KeV5xl
O''~5X1012crn-2 implant FET etc. OXX
A shadow forming active layer 19 is formed. At this time, since it is formed by 81 or the same method, the explanation will be omitted.

Example 2 The present invention is based on the G a A 5 described in the description of the above embodiments.
- It can be applied to semiconductors other than GaA and /As-based semiconductors, and a semiconductor laser with excellent high-speed modulation characteristics can be obtained. In the following explanation, for convenience, FIG. 1 in the above embodiment will be used. This is because the functions, effects, etc. are exactly the same, only the constituent materials are different.

On n-type InP substrate 1, n-type InP layer 2 (thickness 1 μm)
, undoped j no4s Ga ,, A so
, asPo,, 7 Laser active layer 3 (thickness 0.1 μm)
, p-type (12) InP 4 (thickness 1.5 μm [created by single-liquid phase growth method, as the same material as the cladding layer 4 with no cap; 7, n-type InP)! e was used. Wavelength 1.6
Laser oscillation was possible at μm and modulation at 2.5 GHz.

Example 3 On the n-type 1 n P substrate 1, the n-type I rl+), 52
A/(1.4gAs112 (thickness 1.0μm),
n-type 1 no, s B Ga o, 47As layer 3
(thickness 0.12 μm), p-type 'nO,! 12”'0
．． A 48As layer 4 (thickness: 1.0 μm) is grown by molecular beam epitaxial method in a high vacuum. Next, the wave
Without taking it out of the vacuum, a pattern was selectively drawn with an oxygen ion beam to form the high resistivity region 6 gold shown in Example 1. This method allows pattern formation by direct ion implantation without using photoresist.
It is J-Noh.

After ion implantation, using molecular beam epitaxial method,
IIn type 1n O, ff13 (J ao, 47 A
S J @ 0.21t In f formation (13) is made long and used as the active layer of the FET shown in 7. The following description can be omitted since it can be manufactured by the same method as in Example 1.

As detailed above, the present invention is characterized in that a high resistivity layer near the laser element is formed by ion implantation with image energy to electrically isolate the element from the circuit elements and to narrow the current. It is possible to provide a semiconductor laser device equipped with a compact integrated circuit with good electrical characteristics, which is of great industrial benefit.

[Brief explanation of the drawing]

FIG. 1 shows semiconductor layers formed using the present invention: substrate, 2... first cladding layer, 3... active layer, 4...
- Second cladding layer, 5... Cap layer, 6... High specific resistance layer, 7... N-type FET' active layer, 8... Source, 9... Gate, 10... Drain, 12 and 13... Conductive (14) wiring layer, 14... Insulating film, 15... Light emitting region. Special edition y; 1 person (15) \) ■＼ N No. 2 Iris illustration g Group No. q fig.

Claims (1)

[Claims] 1. A step of forming a plurality of semiconductor layers including an active layer for laser emission on a semiconductor substrate, a step of forming a high resistivity region at a predetermined location in the plurality of semiconductor layers by an ion implantation method, and at least A step of providing a semiconductor layer on the high resistivity region, and providing the semiconductor layer with an impurity concentration distribution having a low concentration at least in the circuit and having a concentration peak within the high resistivity region. A method for manufacturing a semiconductor laser device.