JPS6177700A - Nitrogen doping method for group ii-v compound semiconductor - Google Patents

Abstract

PURPOSE:To perform growth of P type group II-VI compd. by pyrolyzing gaseous NH3 at higher temp. than the temp. of a substrate where crystal growth is caused by the thermal decomposition of group II and VI starting material gases, then transporting decomposed NH3 together with the group II and VI starting material gases to the substrate. CONSTITUTION:In the crystal growth basing on thermal decomposition of orga nometallic compd. in a group II and VI compound semiconductor, NH3 is passed through a higher temp. region that the growth temp. of the group II and VI compd. Then, the product generated after passing NH3 is mixed with the starting material gases of the group II and VI compd. and guided to a substrate crystal held at the growth temp. to execute the crystal growth. Thus, doping of N2 of the group II-VI compound semiconductor is accomplished. In the drawing of the apparatus, a substrate crystal 6 is placed on a susceptor 5 and installed in a reaction tube 7. The susceptor is heated by the impression of a high frequency coil 4. The starting material gas 2 is introduced from upstream side into the reaction tube, and NH3 1 is introduced from a separate inlet into the reaction tube after passing through a high temp. region heated by a decomposition furnace 3.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for vapor phase formation of II-Vl group compound semiconductors used in the electronics industry, particularly in the semiconductor industry.

(Prior Art) The doping of (1-2) group compound semiconductors, particularly the p-type doping, has mainly been carried out by mixing H3, etc. into the raw material gas.

(Problems with Prior Art) Vapor phase growth of II-VI group compound semiconductors is usually performed at a low temperature of 500° C. or lower. On the other hand, NI (3jPH
Doping such as Hj AsH3 has a large mass in group V.
.

The deeper the electron level is, the easier it is to form a deep electronic level, making it difficult to function effectively as an acceptor. Therefore, doping with N can be expected to have a particularly great effect. N is usually N)(,
(Journal Opcrystal Growth (J, Crystal Growth) Volume 59,
1-9, 1982), but due to the low substrate temperature, ■
Thermal decomposition of
, must be supplied to the board. This had a negative effect on crystallinity because it caused a side reaction between the raw material gases of group Ⅰ and group Ⅱ and darkness.

(Objective of the Invention) An object of the present invention is to provide a method for easily doping a group I[-VI compound semiconductor with a group II element, particularly N.

(Structure of the Invention) The present invention relates to a vapor phase growth method for forming II-VI group compound semiconductors, which is terminated at a temperature higher than the temperature of the substrate at which group (I) and (II) source gases are thermally decomposed and crystal growth occurs. After the gas is thermally decomposed, it is mixed with the Wataru group and II group raw material gases and transported to the substrate, thereby growing a p-type II-VI compound.

(Operation/Principle of the Present Invention) Since it is usually difficult to form a p-type semiconductor in an ff-VI group compound semiconductor, it is difficult to expect efficient light emission, and its uses are limited. The principle of the present invention, which enables the formation of high-quality pWII-Vl group semiconductors, is as follows. One of the reasons why p-type doping is difficult to perform is that the acceptor level of II-VI group compounds is deep.

An acceptor level is formed by introducing a group V element into a group (i) group of royal elements, but in the former method, the royal elements tend to move in the crystal, making it difficult to obtain stable and reproducible results. Furthermore, in the latter case, the charge at the center increases in the order of NtP#Asp, so the so-called central cell collector tends to increase and the acceptor level tends to become deeper. This corresponds to the fact that excitation of holes from the acceptor level to the valence band becomes difficult to occur at room temperature. Therefore, it is desirable to introduce a lightweight Group V element as an acceptor. However, when N is introduced in the form of NH, the bonding energy of N and H is
It is very difficult to thermally decompose. I[-VI
The growth temperature of the group is often 300 to 500°C, and dissociation at this temperature is almost OK. Therefore, a very large amount of NH3 is required to dope the semiconductor with the required amount, for example l Q"tx-". Since NH3 has strong reactivity, it reacts with group (I) and group (II) source gases, and the reactive components adhere to the substrate surface, significantly impairing the smoothness of the crystal surface. In the present invention, the book is thermally decomposed in advance by passing it through a temperature range higher than the growth temperature (for example, 1000°C), and then mixed with the raw material gases of group ① and group ① and kept at a low temperature. guided to the board. By doing this, N in NH3
can be efficiently introduced into the crystal, and at the same time, unnecessary side reactions can be suppressed. In this way, It is highly doped with acceptors while maintaining high quality crystallinity.
- A Group VI compound can be obtained.

(Example) Finally, an example will be explained using figures. FIG. 1 shows one example in which the present method is applied, in which a susceptor (made of carbon) 5 is placed in a reaction tube 7 on which a substrate crystal 6 is placed.

The susceptor is heated by high frequency waves applied to the high frequency coil 4. Raw material gas (group ■, group ■) 2 is introduced upstream, but NH,1 is introduced from another port, and before being introduced into the reaction tube, it is heated in a high temperature range (e.g., 1000°C) by the decomposition furnace 3. ). NH8 is decomposed here, sent to the reaction tube, mixed with group 1 and group 2 raw materials, and reaches the substrate. In this way, a high-quality II-VI group compound semiconductor is formed to be p-type.

[Brief explanation of drawings]

FIG. 1 is a diagram showing an example of a device embodying the present invention. 3 is a decomposition furnace, 4 is a high frequency coil, 5 is a susceptor, 6 is a substrate crystal, and 7 is a reaction tube.

Claims (1)

[Claims] In organometallic pyrolysis crystal growth of II-VI group compound semiconductors, ammonia (NH_3) is passed through a temperature region higher than the growth temperature of II-VI group compound semiconductors, and then
A method for doping nitrogen into a II-VI group compound semiconductor, characterized by mixing it with a group VI source gas and guiding the mixture to a substrate crystal maintained at a growth temperature for crystal growth.