JP2583543B2 - Heat treatment method for ZnSe or ZnS compound crystal - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a heat treatment method for II-VI group compound crystals, and particularly to a heat treatment method for the purpose of activating an impurity element in a ZnSe or ZnS compound crystal. The present invention also relates to a heat treatment method for a ZnSe or ZnS compound crystal for preventing an increase in crystal structural defects and the like.

[Prior art] Conventionally, impurities for forming a donor or an acceptor are implanted into a semiconductor such as Si as ions or diffused from a diffusion source and introduced, and then heat treatment is performed to activate the impurities. The heat treatment of the semiconductor to be performed is performed.
The condition of the heat treatment is a very important condition because the performance of the obtained semiconductor element is deteriorated when the crystal structural defects increase during the heat treatment, and various studies have been reported.
(For example, “Electronic Technology, Vol. 8,“ Ion Implantation Technology, ”pp. 61-107, Industrial Research Institute (1975)) However, most of the above research reports are related to silicon, which is the most common in the current semiconductor industry, and There are few related to heat treatment of semiconductors. Also, in the report of the compound semiconductor, most of the
This is a report on s, InP and the like, and there is no report on II-VI group compound crystals such as ZnSe.

[Problems to be Solved by the Invention] The present invention relates to the manufacture of an electric element using an electric element using ZnSe (for example, a blue light emitting element), such as a heat treatment after ion implantation and a heat treatment at the time of forming an electrode. An object of the present invention is to provide a heat treatment method capable of preventing an increase in structural defects such as a ZnSe compound during a heat treatment required in the process.

Means for Solving the Problems The present invention has been made to solve the above problems, and in a method of performing heat treatment by heating a ZnSe or ZnS compound crystal, the heat treatment is performed in the compound. Is performed in an atmosphere containing a compound of a Zn element having a relatively low vapor pressure.

As the zinc compound, an organic compound of zinc such as dimethyl zinc and diethyl zinc is preferably used.

The atmosphere containing the Zn element compound is ZnSe or ZnS.
In order to prevent oxidation of the compound crystal of the non-oxidizing atmosphere, it is necessary to use a non-oxidizing atmosphere, and in particular, a trace amount of a Zn compound in an inert gas atmosphere using an inert gas such as N2, Ar, He, Ne, etc. A mixed atmosphere is preferred.

[Operation] In the present invention, the generation of structural defects of ZnSe or ZnS crystals caused by heating in an atmosphere of an inert gas such as N2, He, Ar, Ne, etc. is based on the generation of vacancies generated on the surface. In view of the fact that it is mainly used, the heat treatment is performed in an atmosphere containing a compound of the Zn element, thereby preventing the generation of vacancies of the Zn element.

FIG. 2 is a cross-sectional view schematically showing a heat treatment apparatus used in this example.

The zinc selenide crystal 4 is placed in the furnace core tube 6 after being placed on the support 3. During the heat treatment, a mixed gas in which dimethylzinc was mixed at a rate of 2 × 10 ⁻⁵ mol / min with 4 l / min of H 2 gas was introduced into the furnace core tube 6 from the gas introduction pipe 1 as an atmosphere gas. (The pressure at the exhaust port was normal pressure.) The infrared lamp 2 was used for heating, and the temperature was measured by a thermocouple 7 built in the support 3.

Under the above conditions, the zinc selenide crystal was heated until it reached 700 ° C., kept for 5 minutes, and allowed to cool.

A light-emitting device was prepared using the heat-treated zinc selenide crystal, and the spectral intensity of the emitted light was measured. The result is shown in FIG.

Comparative Example-1 A zinc selenide crystal was heat-treated under the same conditions as in the example except that the flow rate of H2 gas was changed to 4 l / min as an atmosphere gas.

FIG. 3 shows the spectral luminous intensity of a light emitting device using the zinc selenide crystal. It is apparent from FIG. 3 that the heat treatment of this comparative example strongly generates light emission (Self Activated light emission; hereinafter abbreviated as SA light emission) due to the self-compensation effect, which indicates that the crystallinity is deteriorated.

Further, in the above comparative example, the heat treatment temperature was 700 ° C., but it was confirmed that when the ZnSe crystal was treated in a H2 atmosphere at a heat treatment temperature of 500 ° C. or more, the structural defects of ZnSe increased, and the remarkable with the heat treatment time. It turned out to be. Thus, it was found that the effect of the present invention was exhibited in the heat treatment method of ZnSe with respect to the heat treatment at 500 ° C. or more.

In the case of heat treatment of zinc sulfide crystals, it was confirmed that heat treatment at 450 ° C. or more in an H2 atmosphere increased structural defects, and that heat treatment under the same conditions as in this example could suppress SA emission. Was done.

In the above embodiment, an infrared lamp is used for heating the crystal. However, the heating method does not substantially affect the present invention, and any heating method such as resistance heating and high frequency heating can be used.

Further, in the above embodiment, the pressure during the heat treatment was normal pressure, but the atmosphere may be in a reduced pressure state. Further, the concentration of the Zn element compound in the atmosphere is not limited to the above embodiment, but is adjusted based on the pressure, the type of coexisting gas, the heat treatment temperature and the like.

[Effects of the Invention] According to the present invention, a high-temperature heat treatment of a ZnSe or ZnS compound such as a heat treatment after ion implantation on a ZnSe or ZnS compound can be performed without increasing structural defects, and an electronic device having good characteristics (for example, Blue light-emitting element).

[Brief description of the drawings]

FIG. 1 is a diagram showing the spectral intensity of emitted light of a ZnSe light emitting device heat-treated at 700 ° C. using the present invention, FIG. 2 is a cross-sectional view schematically showing a heat treatment apparatus used in the embodiment, and FIG. In the atmosphere
FIG. 3 is a diagram showing the spectral photometric intensity of light emitted from a ZnSe light emitting device that has been heat-treated at 700 ° C.

Claims (2)

(57) [Claims] 1. A heat treatment method for a ZnSe or ZnS compound crystal, comprising heating a ZnSe or ZnS compound crystal or a mixed crystal thereof in an atmosphere containing Zn or Zn compound. 2. The ZnSe or the Zn compound according to claim 1, wherein the Zn compound is dimethyl zinc or diethyl zinc.
Heat treatment method for ZnS compound crystal.