JPH01785A - Mask semiconductor laser manufacturing method - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a mask semiconductor laser, that is, a semiconductor laser having a light-shielding mask having a pinhole-shaped exit hole.

(Prior Art) In optical memories and magneto-optical memories, the recording density can be increased by reducing the spot diameter of the laser beam irradiated onto the recording medium.

When a laser beam is passed through an extremely small pinhole.

It has been experimentally found that the beam diameter of light passing through a pinhole is approximately equal to the pinhole diameter in the so-called near field near the pinhole, and the recording medium is irradiated with a small diameter laser beam in the near field. A method has been proposed, and a mask semiconductor laser has been proposed as a light source for such a small diameter laser beam. The mask semiconductor laser acts as a substantially ideal point light source for optical systems of normal dimensions, and is therefore also useful as a point light source.

(Problems to be Solved by the Invention) Conventionally proposed manufacturing methods for mask semiconductor lasers include forming a light-blocking mask on the light-emitting end face of a semiconductor laser (hereinafter abbreviated as LD); The LD is manufactured by turning on the LD and removing or optically making the mask part transparent to form the injection hole.
There are problems such as the need to pass a large shameful current to D.

Accordingly, an object of the present invention is to provide a novel method for manufacturing a mask semiconductor laser, which can reduce restrictions on the mask material and form an injection hole with a smaller drive current.

(Means for solving the problems) The present invention will be explained below. In the present invention, a mask semiconductor laser (hereinafter abbreviated as mask LD) is manufactured as follows.

After forming a light-blocking mask on the light-emitting end surface of the LD, that is, a mask capable of blocking laser light emitted from the LD,
The LD is turned on in a vacuum container under reduced pressure, and a portion of the mask is removed by emitted laser light to form a pinhole-shaped injection hole.

That is, the feature of the present invention is that the LD with a mask formed thereon is turned on in a vacuum container under a reduced pressure state, and the emitted laser light is used to form an injection hole. Inside the vacuum container,
Vacuum degree 1 below 10-”torr, e.g. 10-1 to 1
It is kept in the range 0-'torr. The injection hole.

It is formed by evaporating and removing a portion of the mask using the thermal energy of the laser beam emitted by the LD.

As for the LD, the wavelength of 780 nm is currently commercially available.

AlGaAs represented by 830nm semiconductor laser
For example, a ternary LD can be mentioned.

The mask may be formed as a single mask layer on the light emitting end face of the LD using an electrically insulating material, or it may be formed on the light emitting end face of the LD using a non-electrically insulating material as a mask layer and an insulating layer.
It may be formed into a structure.

The material of the mask layer is generally required to meet two conditions: it does not transmit the laser beam emitted by the LD, and it melts and evaporates due to the thermal energy of the laser beam. A material that satisfies these conditions is A u *
A g v Cr t I n s A 1 e Z
Metals such as n and their compounds, Se, Dine,
Amphoteric metals such as Sn and their compounds, carbon, S,
Examples include non-metals such as Ge and Si, compounds thereof, and organic materials such as phthalocyanine and cyanine dyes.

Further, the insulating layer is a layer of an electrically insulating material, and when the mask layer is not electrically insulating, it is interposed between the light emitting end surface of the LD and the mask layer. This insulating layer is required to be transparent to the laser beam emitted by the LD, and its materials include SiO, SiO□, A1zO3, S
Examples include iJ49MgFz and TiO□.

(Function) As described above, in the present invention, the LD with the mask formed thereon is turned on in a vacuum container, and the mask layer is evaporated by the thermal energy of the laser beam emitted by the LD.

Since the vacuum container is under reduced pressure, the evaporation of the mask layer material is much more accelerated than under normal pressure.

(Example) Hereinafter, four specific examples will be given. In either embodiment, a mask LD having the form shown in the figure is manufactured. That is, in FIG. 1, the reference numeral 10 indicates the mask LD. 12 indicates LD, 14 indicates 14 edge layer, 1
6 indicates a mask layer, respectively.

Further, the symbol PH indicates a pinhole-shaped injection hole.

The insulating layer 14 and the mask layer 16 constitute a mask.

In any of the examples, the semiconductor laser is (GaA1)
As double hetero type was used. Maximum rated output is 5m
W, continuous operation output is 3+ OK! , one wavelength of oscillation is 78
It is 0 nm.

Example 1 A thin SiO film having a thickness of 2100 mm was formed on the injection end face, that is, the injection cleavage plane, of the LD by vacuum evaporation using a resistance heating method to form an insulating layer 14. The vapor deposition conditions are as follows.

Evaporation source material: SiO purity 99.99% Evaporation source temperature:
1200'C Evaporation source boat: Molybdenum Vacuum degree: 2xlO-'torr LD end surface temperature: 20-40'', on the insulating layer.

Vapor deposition source material: zn purity 99.99% Vapor deposition source temperature,
700 @C Vapor deposition source boat: Molybdenum Vacuum degree: 2xlO-Storr Zn was deposited to a thickness of 2000 °C using the resistance heating method under the deposition conditions of LD end face temperature = 20 to 40 °C.
The mask layer 16 was formed by vapor deposition.

Hereinafter, the LD formed with the insulating layer and the mask layer will be referred to as a material.

The material prepared as above was heated to a degree of vacuum of 1 x lO-'ta.
When I put it in a vacuum container that was depressurized to RR and monitored the current while turning on the LD, when the injection current was increased to 50+oA, the monitored current changed rapidly, so I assumed that an injection hole was formed in the mask layer. When I judged it and observed it with an electron microscope at a magnification of 15,000 times, it was found that: ■, 0 microns x 1
．． It was confirmed that an injection hole of 3 microns was formed.

For comparison, when the same material as above was lit in the atmosphere and an injection hole was formed, the injection current was 73 mA and the injection hole was 1.0 mA.
An injection hole with a size of 1.2 mm x 1.2 mm was formed.

Example 2 SiO was deposited on the above LD to a thickness of 21 cm under the same vapor deposition conditions as in Example 1.
00 to form an insulating layer, and evaporation source material 2T is applied on top of it.
i 99.99% purity Evaporation source temperature: ~2000aC Evaporation source boat: Tungsten Vacuum degree: 2xlO-'torr LD end surface temperature: 20-40'C Ti was deposited to a thickness of 1500aC by resistance heating method under the following evaporation conditions.
The mask layer 16 was formed by vapor deposition.

The material prepared as described above was heated to a degree of vacuum of 1 xi (1-st
When I placed it in a vacuum container with a reduced pressure of 100 mA and monitored the current while turning on the LD, I found that when the injection current was set to 98 mA, the monitored current changed rapidly.

It was determined that injection holes were formed in the mask layer, and when observed with an electron microscope at a magnification of 15,000 times, it was confirmed that injection holes of 0.8 micron xo and 9 micron were formed.

For comparison, an attempt was made to form an injection hole by lighting the same material as above in the atmosphere, but in the end it was not possible to form an injection hole.

Example 3 SiO was deposited to a thickness of 21 cm on the above LD under the same vapor deposition conditions as in Example 1.
00 to form an insulating layer, and evaporation source material 2G is applied on top of it.
e Purity 99.991 Evaporation source temperature: 1200°C Evaporation source boat: Tungsten Vacuum degree: 1xlO-'torr LD end surface temperature = 20~406C Ge was deposited to a thickness of 3500°C by resistance heating method. This was used as a mask layer IB.

The material prepared as above was heated to a vacuum degree of 1 x lO-'to
When I placed it in a vacuum container with reduced pressure to RR and monitored the current while turning on the LD, when I set the injection current to 671 people, the monitored current changed rapidly.

It was determined that an injection hole was formed in the mask layer, and when observed with an electron microscope at a magnification of 15,000 times, it was found that the diameter was 0.
It was confirmed that a circular injection hole of 9 microns was formed.

For comparison, when the same material as above was lit in the atmosphere and an injection hole was formed, the diameter was 1 with an injection current of 82+aA.
．． A circular injection hole with a diameter of 0 mm and 90 mm was formed.

Example 4 SiO was deposited to a thickness of 21 cm on the above LD under the same vapor deposition conditions as in Example 1.
00 to form an insulating layer, and evaporation source material on it:
Au Ge alloy purity 99.99% Vapor deposition source temperature: 1
200°C Evaporation source boat: Tungsten Vacuum degree: 1xlO-'torr LD end face temperature: 20 to 40''C By the resistance heating method, AuGe alloy was evaporated to a thickness of 4,000 mm to form the mask layer 16. I did.Au-
The weight ratio of the Ge alloy is 50:50.

The material prepared as above was vacuumed to 1xlO-'t.

When the current was monitored while the LD was turned on, the monitored current suddenly changed when the injection current was set to 83 mA, indicating that an injection hole had been formed in the mask layer. The diameter was determined to be 0.8 micrometers when observed using an electron microscope at a magnification of 10,000 times.
It was confirmed that a circular injection hole was formed.

For comparison, when the same material as above was lit in the atmosphere and an injection hole was formed, the injection hole had a diameter of 0 with an injection current of 98+nA.
, a micron circular injection hole was formed.

(Effects) According to the present invention, a novel method for manufacturing a mask semiconductor laser can be provided.

As described above, in this method, the injection holes are formed in a vacuum vessel under reduced pressure, so the evaporation of the material of the mask layer is accelerated compared to the conventional method in which the injection holes are formed in the atmosphere. This makes it possible to form injection holes even in mask layers made of materials that cannot form injection holes in the atmosphere, greatly easing restrictions on mask materials, and allowing injection with a lower injection current than conventional methods. Pore formation becomes possible.

[Brief explanation of the drawing]

The figure is a diagram showing, as an explanatory diagram, one example of the form of a mask semiconductor laser manufactured according to the present invention. 10., mask semiconductor laser, 12. ,, semiconductor laser, 14. , , insulating layer, 16. ,, mask layer (constituting a mask together with the insulating layer 14) + PH,,
, pinhole-shaped injection hole

Claims (1)

[Claims] After forming a light-shielding mask on the light emitting end face of the semiconductor laser, the semiconductor laser is turned on in a vacuum container under reduced pressure, and a part of the mask is removed by the emitted laser light to form a pinhole. 1. A method of manufacturing a mask semiconductor laser, the method comprising forming a shaped injection hole.