JPH0629227A - Crystal growth method - Google Patents

Abstract

PURPOSE:To obtain a high-carrier-concentration N-doped II-VI compound semiconductor without a need for a high-cost apparatus by a method wherein, in a crystal growth method which grows the compound semiconductor, dimethylzinc and a trimethylamine adduct are used as growth raw materials or doping raw materials. CONSTITUTION:While AsH3 is being supplied to a reaction tube 11, the temperature of a substrate 12 is raised and the surface of the substrate is cleaner. Dimethylzinc which is housed in a bubbler 1a is bubbled by H2; in the same manner, dimethylselenium which is housed in a bubbler 1b and a trimethylamine adduct (DMZn.TMN) which is housed in a bubbler 1c are bubbled respectively by H2. After the supply of the AsH3 has been stopped, the respective organic raw materials are supplied to the reaction tube 11. The supply amount of the DMZn.TMN is changed in a range of 0.1 to 10% with reference to the amount of DMZn. A ZnSe growth film is obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a crystal growth method, and more particularly to a crystal growth method for II-VI group compound semiconductors.

[0002]

2. Description of the Related Art II-VI group compound semiconductors, in particular wide-gap semiconductors represented by ZnSe, are attracting attention as light-emitting device materials in the blue region, and research on device development is underway. The problem with these light emitting materials is that it is difficult to obtain a p-type conductive semiconductor. This is due to problems peculiar to wide-gap materials such as the activation rate of impurities, the stability of electrical characteristics, the depth of impurity levels, and the self-compensation effect of impurities. However, in recent years, nitrogen (N) has particularly attracted attention as an impurity exhibiting p-type conduction,
Now, p-type conduction ZnSe can be obtained.

As a conventional N-doped ZnSe growth method, a method using a metal organic chemical vapor deposition method (MOCVD method) is used. Japanese Journal of Applied Physics
Volume 27, No. 5, 1988, L909-L912. The molecular beam epitaxy method (MBE method) is applied to Applied Physics Letters (Applied
Physics Letters) Vol. 57, No. 20, 1990, pp. 2127-2
See page 129. Among them, the first conventional method is diethyl zinc (Zn (C
₂ H ₅ ) ₂ ; DEZn) and hydrogen selenide (H ₂ Se) are used, and NH ₃ is used as a N doping material. The semiconductor substrate placed in the quartz reaction tube is heated to 350 ° C.,
N-doped ZnSe is grown by introducing each source gas into the reaction tube. A second conventional method is a method in which a semiconductor substrate is irradiated with molecular beams of zinc and selenium under ultrahigh vacuum using an MBE apparatus to grow ZnSe. For N-doping, N ₂ is plasma-decomposed by high-frequency discharge and the substrate is irradiated with this decomposed gas. At this time, the substrate temperature was 275 ° C.

[0004]

SUMMARY OF THE INVENTION In the first conventional method,
It has been found that N is doped in ZnSe at 10 ¹⁹ cm ⁻³ or more. However, the carrier concentration is 10 ¹⁴
The film has a resistivity of 10 cm ^-3.
It was a very high value of ² to 10 ³ Ωcm. ZnSe is the reason why the carrier concentration is low, that is, the activation rate is low.
It is known that each N doped in the film is bonded to one H molecule, and that N does not act as a carrier source. On the other hand, in the second conventional method, the obtained N
The carrier concentration of the doped ZnSe film is 3.7 × 10 ¹⁷
cm ^-3 has been obtained. However, this method requires a power supply for generating high-frequency discharge and a special discharge cell, and has a problem that it can be realized only by an ultra-high vacuum apparatus which is extremely expensive as a growth apparatus. The present invention solves such conventional problems and provides a crystal growth method by which an N-doped II-VI group compound semiconductor having a high carrier concentration can be obtained without requiring an expensive apparatus. The purpose is to

[0005]

The first aspect of the present invention is to provide a crystal growth method for growing a compound semiconductor, wherein a chemical formula (CH ₃ ) ₂ Zn.N is used as a growth raw material or a doping raw material.
A crystal growth method characterized by using a dimethylzinc / trimethylamine adduct represented by (CH ₃ ) ₃ . A second aspect of the present invention is, in a crystal growth method for growing a compound semiconductor, a dimethylzinc / triethylamine adduct represented by the chemical formula (CH ₃ ) ₂ Zn.N (C ₂ H ₅ ) ₃ is used as a growth raw material or a doping raw material. It is a crystal growth method characterized by using it.

A third aspect of the present invention is a crystal growth method for growing a compound semiconductor, wherein a diethylzinc compound represented by the chemical formula (C ₂ H ₅ ) ₂ Zn.N (CH ₃ ) ₃ is used as a growth material or a doping material. It is a crystal growth method characterized by using trimethylamine adduct. A fourth aspect of the present invention is a crystal growth method for growing a compound semiconductor,
As a growth raw material or a doping raw material, a chemical formula (C ₂
H ₅₎ is a crystal growth method, which comprises using a _{2 Zn · N (C 2 H} 5) Diechiru zinc triethylamine adduct represented by _3.

[0007]

The dimethylzinc / trimethylamine adduct, the dimethylzinc / triethylamine adduct, the diethylzinc / trimethylamine adduct and the diethylzinc / triethylamine adduct according to the present invention can be used in the MOCVD method which is widely used as a growth method for compound semiconductors. Similarly, it can be used for an ultra-high vacuum device such as MBE, and a special decomposition cell such as a high frequency discharge cell is not particularly required. Also, like NH ₃ , N
Since there is no —H direct bond, the N atoms doped in the compound semiconductor are rarely compensated by H, and a growth film with a high carrier concentration can be obtained.

[0008]

EXAMPLES Next, examples of the present invention will be described in detail. Example 1 FIG. 1 is a schematic configuration diagram of a crystal growth apparatus used in this example. The growth apparatus used is configured to heat the substrate 12 installed in the reaction tube 11 by induction heating of the high frequency coil 13. Further, a plurality of organic raw materials other than AsH ₃ are supplied to the reaction tube 11 by using H ₂ as a carrier gas by bubbling H ₂ . In this embodiment, a case will be described in which GaAs is used as a substrate and ZnSe is grown. The growth procedure is as follows.

The substrate 12 was heated to 580 ° C. while supplying AsH ₃ to the reaction tube 11, and the surface of the substrate was cleaned for 10 minutes. Dimethylzinc (DMZn) contained in the bubbler 1a was bubbled with H ₂ , and similarly dimethylselenium (DMSe) contained in the bubbler 1b, and dimethylzinc trimethylamine adduct (DMZn TMN) contained in the bubbler 1c. Respectively H
I bubbled at ₂ . Set the substrate temperature to 500 ° C and
After stopping the supply of sH ₃ , the respective organic raw materials were supplied to the reaction tube 11. The flow rate of DMZn at this time is 0.5
The flow rate of sccm and DMSe is 1 sccm, the carrier H ₂ is 5000 sccm, and the pressure of the reaction tube is 76 Tor.
set to r. The supply amount of DMZn / TMN is DMZn
The growth amount of ZnSe was changed in the range of 0.1% to 10% to obtain a ZnSe growth film.

The surface of the obtained ZnSe film is a mirror surface,
The maximum value of carrier concentration was 8.6 × 10 ¹⁶ cm ⁻³ . Regarding carrier concentration, growth temperature, DMSe / D
The carrier concentration fluctuates with a change in the MZn supply ratio, and a higher carrier concentration can be obtained. Similarly, DMZn TMN
Of 100%, that is, DMZn is not used, DM
Growth was tried even when Zn.TMN was used as a growth raw material. Other growth conditions used the above-mentioned conditions. The carrier concentration remained at 10 ¹⁶ cm ^-3 , but p-type ZnSe with a mirror surface was used.
was gotten.

Example 2 The crystal growth apparatus used in this example is the same as that used in Example 1. In this embodiment, a case will be described in which GaAs is used as a substrate and ZnSe is grown. The growth procedure is as follows. The substrate 12 was heated to 580 ° C. while supplying AsH ₃ to the reaction tube 11, and the surface of the substrate was cleaned for 10 minutes. Dimethylzinc (DMZn) contained in the bubbler 1a was bubbled with H ₂ , and similarly diethylselenium (DESe) contained in the bubbler 1b, and dimethylzinc-triethylamine adduct (DMZn ・ TE) contained in the bubbler 1c.
Each N) was bubbled with H ₂ . Substrate temperature is 45
After setting the temperature to 0 ° C. and stopping the supply of AsH ₃ , each organic raw material was supplied to the reaction tube 11. DMZ at this time
The flow rate of n is 0.5 sccm, the flow rate of DESe is 1 sccc
m, the carrier H ₂ was set to 5000 sccm, and the pressure in the reaction tube was set to 76 Torr. The supply amount of DMZn · TEN was changed in the range of 0.1% to 10% with respect to the amount of DEZn to obtain ZnSe growth films.

The surface of the obtained ZnSe film is a mirror surface,
The maximum value of carrier concentration was 5.5 × 10 ¹⁶ cm ^-3 . Similarly, the supply amount of DMZn · TEN is set to 100
%, That is, without using DMZn, an attempt was made to grow even when DMZn.TEN was used as a growth raw material. Other growth conditions used the above-mentioned conditions. Carrier concentration is 10 ¹⁶ cm ^-3
However, p-type ZnSe having a mirror surface was obtained.

Example 3 The crystal growth apparatus used in this example is the same as that used in Example 1. In this embodiment, a case will be described in which GaAs is used as a substrate and ZnSe is grown. The growth procedure is as follows. The substrate 12 was heated to 580 ° C. while supplying AsH ₃ to the reaction tube 11, and the surface of the substrate was cleaned for 10 minutes. Diethylzinc (DEZn) contained in the bubbler 1a was bubbled with H ₂ , and similarly diethylselenium (DESe) contained in the bubbler 1b and diethylzinc trimethylamine adduct (DEZn.TM) contained in the bubbler 1c.
Each N) was bubbled with H ₂ . Substrate temperature is 45
After setting the temperature to 0 ° C. and stopping the supply of AsH ₃ , each organic raw material was supplied to the reaction tube 11. DEZ at this time
The flow rate of n is 0.5 sccm, the flow rate of DESe is 1 sccc
m, the carrier H ₂ was set to 5000 sccm, and the pressure in the reaction tube was set to 76 Torr. The supply amount of DEZn.TMN was changed in the range of 0.1% to 10% with respect to the amount of DEZn to obtain ZnSe growth films.

The surface of the obtained ZnSe was a mirror surface, and the maximum carrier concentration was 6 × 10 ¹⁶ cm ^-3 . Similarly, the growth was tried even when the supply amount of DEZn.TMN was 100%, that is, when DEZn.TMN was used as a growth raw material without using DEZn. Other growth conditions used the above-mentioned conditions. Although the carrier concentration remained at 10 ¹⁶ cm ^-3 , p-type ZnSe having a mirror surface was obtained.

Example 4 The crystal growth apparatus used in this example is the same as that used in Example 1. In this embodiment, a case will be described in which GaAs is used as a substrate and ZnSe is grown. The growth procedure is as follows. The substrate 12 was heated to 580 ° C. while supplying AsH ₃ to the reaction tube 11, and the surface of the substrate was cleaned for 10 minutes. Diethylzinc (DEZn) contained in the bubbler 1a was bubbled with H ₂ , and similarly diethylselenium (DESe) contained in the bubbler 1b and diethylzinc-triethylamine adduct (DEZn TE) contained in the bubbler 1c.
Each N) was bubbled with H ₂ . Substrate temperature is 45
After setting the temperature to 0 ° C. and stopping the supply of AsH ₃ , each organic raw material was supplied to the reaction tube 11. DEZ at this time
The flow rate of n is 0.5 sccm, the flow rate of DESe is 1 sccc
m, the carrier H ₂ was set to 5000 sccm, and the pressure in the reaction tube was set to 76 Torr. The supply amount of DEZn · TEN was changed in the range of 0.1% to 10% with respect to the amount of DEZn to obtain ZnSe growth films.

The surface of the obtained ZnSe film is a mirror surface,
The maximum value of carrier concentration was 2 × 10 ¹⁶ cm ^-3 . Similarly, the growth was tried even when the supply amount of DEZn.TEN was 100%, that is, when DEZn.TEN was not used and DEZn.TEN was used as the growth raw material. Other growth conditions used the above-mentioned conditions. Although the carrier concentration remained at 10 ¹⁶ cm ^-3 , p-type ZnSe having a mirror surface was obtained.

Although ZnSe is used as the compound semiconductor to be grown in the above embodiment, it is obvious that other materials such as ZnS, ZnSSe, ZnMnS and ZnMnSe may be used in the present invention. Further, the substrate may be another substrate such as Ge or InP. Although the vapor phase growth apparatus is used as the growth apparatus in the above-described embodiments, the present invention is not limited to this, and a MONBE method or the like in which crystal growth is performed using an organic metal raw material as a molecular beam source may be used.

[0018]

As described above, according to the present invention, a p-type compound semiconductor having a high carrier concentration can be grown at a low cost by using a conventionally used crystal growth system. The film obtained by the method of the present invention can be used for a blue semiconductor light emitting device and is industrially useful.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of an example of a growth apparatus used in the method of the present invention.

[Explanation of symbols]

 1a-1c Bubbler 11 Reaction tube 12 Substrate 13 High frequency coil

Claims (4)

[Claims] 1. A crystal growth method for growing a compound semiconductor, wherein dimethylzinc / trimethylamine adduct represented by the chemical formula (CH ₃ ) ₂ Zn.N (CH ₃ ) ₃ is used as a growth material or a doping material. And a crystal growth method. 2. A crystal growth method for growing a compound semiconductor, wherein dimethylzinc / triethylamine adduct represented by the chemical formula (CH ₃ ) ₂ Zn.N (C ₂ H ₅ ) ₃ is used as a growth material or a doping material. A method for growing a crystal characterized by: 3. A crystal growth method for growing a compound semiconductor, wherein a diethylzinc / trimethylamine adduct represented by the chemical formula (C ₂ H ₅ ) ₂ Zn.N (CH ₃ ) ₃ is used as a growth material or a doping material. A method for growing a crystal characterized by: 4. A crystal growth method for growing a compound semiconductor, wherein diethylzinc / triethylamine adduct represented by the chemical formula (C ₂ H ₅ ) ₂ Zn.N (C ₂ H ₅ ) ₃ is used as a growth material or a doping material. A crystal growth method characterized by using.