JP2740681B2 - Method for manufacturing compound semiconductor thin film - Google Patents

Description

The present invention relates to a method for producing a compound semiconductor thin film, and more particularly to a method for producing a compound semiconductor thin film.
TECHNICAL FIELD The present invention relates to a method for producing a Zn-VIb group compound semiconductor thin film having type conductivity characteristics.

[Conventional technology]

In recent years, ZnS and ZnSe, which have attracted attention as blue light-emitting materials,
As a method for producing such compound semiconductor thin films, a method called metal organic vapor phase epitaxy (MOVPE) is often employed. In this MOVPE method, for example, an organometallic compound containing a Group IIb element such as diethylzinc [(C ₂ H ₅ ) ₂ Zn] is thermally decomposed in the gas phase, and VI metal such as hydrogen selenide (H ₂ Se) is decomposed. By reacting with a compound containing a group b element, a Zn-VI group b compound semiconductor thin film such as ZnSe has been grown on a substrate. Further, in order to produce a light-emitting element with high efficiency, it is necessary to form a pn junction by controlling conductivity, and various dopants have been studied. For example, to realize n-type conduction characteristics, Ga, In,
Halogen elements have been studied and high carrier concentration and high mobility have been achieved. In order to realize p-type conduction, P, As, or N, which is an Ia group element such as Li or a Vb group element, is being studied.

[Problems to be Solved by the Invention] However, it has been difficult to provide excellent p-type conductivity. It is said that the reason is that the use of the P and As elements makes it easier to form deep impurity levels, and the emission wavelength is not blue. In addition, nitrogen element easily forms a shallow acceptor level and is regarded as a promising blue light-emitting material. However, there has been a problem that the activation rate of doped nitrogen is low, the carrier concentration is low, and the conduction characteristics are poor.

An object of the present invention is to solve the problems of the prior art and to provide an excellent p
An object of the present invention is to obtain a Zn-VIb group compound semiconductor thin film having a type conduction characteristic.

[Means for solving the problem]

In order to achieve the above object, a method for producing a compound semiconductor thin film of the present invention includes, in a reaction vessel, a compound containing Zn of a group IIb element of the periodic table, a compound containing at least one of group VIb elements, In addition, a compound containing at least nitrogen and zinc is introduced in a gas phase, and these are thermally decomposed to produce a Zn-VIb group compound semiconductor thin film on a substrate provided in the reaction vessel.

[Action]

The present invention has been completed by finding that when a compound containing nitrogen and zinc is used as a dopant, not only the efficiency of taking in the nitrogen element is improved, but also the activation rate is improved.

In order to carry out nitrogen doping in the present invention, a compound containing nitrogen and zinc may be introduced into a reaction vessel in the MOVPE method. At this time, since the nitrogen atom is taken into the crystal together with the zinc atom, the nitrogen atom easily enters the group VIb site and is easily activated as a p-type dopant.
Table 1 shows specific examples, but the present invention is not limited by these.

Many of the starting compounds used in the present invention are solid at room temperature and have a low vapor pressure. Therefore, during actual use, it is necessary to take measures such as heating the raw material storage cylinder and the piping system. Raw materials that are liquid at room temperature can be introduced into the reaction vessel by bubbling as in the related art.

〔Example〕

 Hereinafter, the present invention will be described in detail with reference to examples.

FIG. 1 is a system diagram showing a configuration of an apparatus when the present invention is applied to the production of a single crystal film of a ZnSe compound semiconductor thin film. In the figure, liquid diethyl zinc [(C ₂ H ₅ ) ₂ Zn] which is a raw material containing a Zn element constituting a ZnSe compound semiconductor
Is bubbled in the bubbler container 5 in which the gas flow rate is controlled by the gas flow rate controller 9 to form a hydrogen gas containing a necessary amount of diethyl zinc, and a doping compound for adding impurities therein is formed.
Here, a predetermined flow rate of hydrogen gas passed through the container 7 containing bis (3-N, N-dimethylaminopropyl) zinc is added as a raw material, while Se forming a ZnSe compound semiconductor is formed.
A required amount is supplied from a gas cylinder 6 filled with hydrogen selenide, which is a raw material containing an element, through a flow rate controller 12 and a predetermined flow rate of hydrogen gas is added thereto through a flow rate controller 11 to obtain a raw material. Together with a raw material gas containing diethyl zinc and bis (3-N, N-dimethylaminopropyl) zinc in the gas phase. In a reaction vessel 1, a GaAs substrate 3 is placed on a substrate holder 2 and is heated to a predetermined temperature by a high-frequency heating coil 4 to form a p-type conductive ZnSe compound semiconductor containing nitrogen by a chemical vapor reaction. A single crystal thin film is formed on a substrate. The lattice constant mismatch between GaAs and ZnSe is less than 1%,
A good single crystal thin film can be formed. This lattice constant mismatch is allowed up to about 5%, and InP, Si, and the like can be used as the substrate. 8 and 9 are gas flow controllers, 13
Is an exhaust port.

More specifically, the production of the compound semiconductor described above will be described. Hydrogen gas passing through a bubbler container 5 of diethyl zinc at a temperature of 5 ° C. at 25 cc / min and bis (3-N, N
-Dimethylaminopropyl) 5c passed through zinc container 7
The raw material gas after mixing and diluting c / min hydrogen gas with 1 / min hydrogen gas is introduced into the reaction vessel 1. At the same time, a raw material gas diluted with hydrogen gas, 5 vol% hydrogen selenide gas, 100 cc / min, was further diluted and mixed with 1 / min hydrogen gas, and then introduced into the reaction vessel 1 and heated to a temperature of 400 ° C. By spraying on the substrate 3, a ZnSe single crystal thin film containing nitrogen was grown at a rate of 2 μm per hour. ZnSe obtained
The surface of the single-crystal thin film had no problem in crystallinity in which a good mirror surface was formed. The resistance value of the ZnSe single crystal thin film is
When no bis (3-N, N-dimethylaminopropyl) zinc was added and when dopants other than nitrogen, such as As and P, were included, the resistance was higher than 10 ⁶ Ω · cm. When 3- (N, N-dimethylaminopropyl) zinc was used, a low resistance value of several tens Ω · cm or less was exhibited. The p-type carrier concentration was 10 ¹⁶ / cm ³ or more, and the addition amount could be increased by one digit or more compared to the case where conventional ammonia was used as a nitrogen source.

The impurity memory effect (effect on the next growth of the semiconductor thin film) is an important factor when adding impurities. In this embodiment, bis (3-N, N-dimethylaminopropyl) zinc Since the adhesion to the pipe was small, no problem occurred in this point. Further, when the other compounds containing nitrogen and zinc shown in Table 1 were used, the same effect as that of the present example was obtained.

Although the embodiment of the present invention has been specifically described above, the present invention is not limited to the above embodiment, and it is needless to say that various changes can be made without departing from the gist of the present invention.

〔The invention's effect〕

As described above, according to the method for producing a compound semiconductor thin film according to the present invention, since a zinc-based organometallic compound containing nitrogen is used, in the production of a Zn-VIb group compound semiconductor thin film, There is an advantage that a high-quality compound semiconductor thin film that emits blue light and has good p-type conductivity can be obtained.

[Brief description of the drawings]

 FIG. 1 is a system diagram showing a configuration of an apparatus for manufacturing a ZnSe single crystal thin film used in an embodiment of the present invention. DESCRIPTION OF SYMBOLS 1 ... Reaction container 2 ... Substrate holder 3 ... GaAs substrate 4 ... High frequency heating coil 5 ... Bubbler container 6 ... Hydrogen selenide gas cylinder 7 ... Container of zinc-containing organometallic compound containing nitrogen 8, 9, 10, 11, 12 ... gas flow controller 13 ... exhaust port 14 ... hydrogen gas

Claims (1)

(57) [Claims] 1. A reaction vessel containing a group IIb element of the periodic table
A compound containing Zn, a compound containing at least one of Group VIb elements, and a compound containing at least nitrogen and zinc are introduced in a gas phase, and these are thermally decomposed to form Zn on a substrate placed in the reaction vessel. -A method for producing a compound semiconductor thin film, comprising producing a group VIb compound semiconductor thin film.