JPS62229846A - Manufacture of ii-vi compound semiconductor element - Google Patents

Abstract

PURPOSE:To obtain a high quality, II-VI compound semiconductor element without lattice defects, by heating a group II molecular beam and a group VI molecular beam with a heater, thereby obtaining high temperature molecular beam, and setting the temperature of a growing substrate at a low temperature in a temperature range, where a single crystal having a stoichiometric composition can be grown. CONSTITUTION:A semiconductor growing apparatus 1 is provided with the following parts: a gas cell 3, which is protruded in a chamber 2; Knudsen cells 4 and 5; a growing substrate 6, which is arranged in the chamber 2; and a substrate stage 7, which supports the substrate 6 and has a heater in the inside. A cracking heater, which is used for decomposing molecules in the cruster state in group-II and group-VI molecular beams, is heated to a high temperature. the molecules are decomposed with the cracking heater. Energy for surface migration is also imparted. Thus high energy molecular beams are obtained. The temperature of the growing substrate 6 is set at a low temperature in a temperature range, where a single crystal having a stoichiometric composition can be grown.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is directed to II, which is considered to be the most promising blue-emitting material.
- A method for manufacturing a Vl group compound semiconductor device.

[Conventional technology]

Molecular beam epitaxial growth (hereinafter abbreviated as MBE) is a method for manufacturing half-W body elements, including vapor phase epitaxy,
Various studies are being conducted on this method because it is possible to keep the temperature of the growth substrate lower than in the liquid phase growth method and to minimize lattice defects such as vacancies. Among these, research is being conducted to apply MBE to the production of It-Vl group compound semiconductor devices, which are considered promising as blue-emitting materials.
JP-A-58-86.731, JP-A No. 60-143,680
The number etc. are known.

If high-quality II-Vl group compound semiconductor devices can be manufactured and P-type and N-type conductivity can be controlled, progress in optoelectronic devices such as blue light-emitting diodes and short wavelength lasers will be possible. Practical use of group compound semiconductor devices as light-emitting materials has not yet been reached.

[Problems with conventional technology]

The reasons why the above-mentioned group elements have not been put to practical use include the difference in vapor pressure at the same temperature between group III elements and group III elements, strong ionic bonding, the tendency to form lattice defects due to the incorporation of impurities, and self-compensation. Examples include the fact that the effect is likely to occur.

Since the growth substrate temperature can be kept low in MBE, lattice defects due to the generation of vacancies and the incorporation of impurities from the substrate are less likely to occur than in the past, but it is possible to produce high-quality single crystal thin films that can be put to practical use. has not yet been obtained, and the growth of high-quality single-crystal thin films is desired.

[Purpose of the invention]

The present invention was made in view of the above problems, and an object of the present invention is to provide a manufacturing method capable of manufacturing a high quality II-VI group compound semiconductor device with few lattice defects.

[Summary of the invention]

In order to achieve the above object, the present invention raises a cranking heater used for the purpose of decomposing molecules in a cluster state in a molecular beam to a high temperature, and uses the cranking heater to not only decompose molecules but also to generate energy for surface migration. The present invention is characterized in that the temperature of the growth substrate is set to a low temperature range in which growth of a single crystal with a stoichiometric composition is possible. [Example] FIG. 1 shows an example of the present invention, and is a schematic diagram of an apparatus used in an experiment conducted by the present inventors.

In the figure, 1 is a semiconductor growth apparatus, which includes a gas cell 3 extending into a chamber 2, a Knudsen cell 4°5, a growth substrate 6 (GaAs: using gallium arsenide) disposed in the chamber 2, a substrate stand 7 that holds the substrate 6 and has a heater therein; shutters 8 and 9 disposed near the respective molecular beam emission ends of the Knudsen cells 4 and 5;
A shutter 10 disposed near the substrate 6, a Has gas cylinder 11 serving as a gas source for the gas cell 3, a flow control valve 13 connected to the pulp 12 of the cylinder 11, and the flow control valve 13 and the gas cell 3. It is comprised of a variable leak valve 14 that connects the chamber to the chamber, and an exhaust device 15 that maintains the desired pressure inside the chamber. Note that although there are actually devices for RHEED pattern measurement, other exhaust devices, a mass spectrometer, etc., they are omitted here.

FIGS. 2 and 3 are sectional views of essential parts of the gas cell 3 and the Knudsen cell 4, respectively.

In FIG. 2, 16 is a translucent alumina tube, and a cranking heater 17 is disposed inside the translucent alumina tube 16.
Tantalum heat shielding plate 1 on the outer circumference of the translucent alumina tube 16
8 are installed. With these translucent alumina tube 16, cranking heater 17, and tantalum heat shield plate 18,
A gas cell 3 is configured.

In FIG. 3, 19 is a quartz tube, a cranking heater 20 is disposed inside the quartz tube 19, a cell heater 21 is wound around the outer periphery of the quartz tube 19, and the cell heater 21 is fixed on the outside of the cell heater 21. An alumina insulating tube 22 is provided, and a tantalum heat shielding plate 23 is provided on the outer periphery of the alumina insulating tube 22, and the Knudsen cell 4 is constituted by these.

Note that the Knud sensor cell 5 also has the same configuration as the Knud sensor cell 4.

In the above experimental apparatus, Zn (zinc) is placed in the Knudsen cell 4 as a molecular beam source of group Ⅰ elements, dopant is placed in the Knudsen cell 5, and H and S are used as the gas cell sources.
An experiment was conducted using (hydrogen sulfide).

First, an experiment was conducted without doping, with the cracking temperature of the cracking heater 20 of the Knudsen cell 4 set at 850°C, and the cranking heater 17 of the gas cell set at 920°C. On the other hand, when the growth substrate temperature was 360° C., the RHEED pattern shown in FIG. 5 was observed, clearly indicating that the quality of the ZnS crystal was poor at the growth substrate temperature of 310° C.

Next, cracking heater 20 without doping
FIG. 6 shows the RHEED pattern of a thin film grown at a substrate temperature of 220° C. with a gas cell cracking heater temperature of about 900° C. and a gas cell cracking heater temperature of 980° C. Also,
Figures 7 and 8 show the substrate temperature between 220°C and 250°C.
When the temperature was changed to 70°C, no single crystal thin film was obtained at 220°C, but single crystal thin films were obtained at 250°C and 270°C.

FIG. 9 is a graph of X-ray diffraction of a thin film when the RHEED pattern shown in FIG. 7 is taken.

From this figure as well, it can be seen that a single crystal thin film is growing. Figure 10 shows a growth substrate temperature of 220°C, 2
Z in the grown ZnS at three points at 50°C and 270°C
It is a graph showing the ratio occupied by n. Considering the above figures 6 to 8 and the error range of the measuring device, at least 2
It can be said that 50°C falls within the low temperature range in which a single crystal thin film with a stoichiometric composition can be formed.

Next, the growth substrate temperature was set to 250°C, and Ga was added to Zn+S.
The photoluminescence of the single crystal thin film grown by doping (gallium) from the Knudsen cell 5 is the 11th photoluminescence.
The graph of FIG. 12 is a graph showing the resistivity of each single crystal thin film grown while changing the temperature of the Knudsen cell 5.

From these figures 11 and 12, SA luminescence Z as previously reported in photoluminescence is not observed, and the resistivity is as low as several ΩCm from the figure, so Ga is a single-crystal thin film. It is thought that the Zn position of ZnS is substituted.

In this example, the cracking heater was also used in the Knudsen cell 5 in order to give the dopant Ga energy for surface migration on the growth substrate 6 surface. This is because not only the amount but also the heating (cranking heater temperature of about 900° C.) allows effective doping.

FIG. 13 is a diagram showing photoluminescence of a single crystal thin film similarly grown using Ag (silver) as a dopant. From this figure, it appears that Ag replaces the Zn position of ZnS.

This is the conventionally known ZnS containing Ag and Ga.
The photoluminescence of is 2.81eV at 77k
It is said to have a peak at 2, whereas in Fig. 13 it has a peak at
．． It shows a very close value of 88 eV, and this peak is considered to be the emission related to Ag and Ga.
Since the acceptor level of Ag is as deep as +0.6 eV in the valence band, the resistivity is considered to be very high.However, since almost no current flows through the grown film obtained in this example, Ag This is because it is thought that the particles do not remain between the lattices.

Note that although it was mentioned above that Ga is contained in the Ag-doped grown film, this is because Ga is mixed in from the growth substrate 6 even if the growth substrate temperature becomes low.

However, this contamination was reduced by lowering the substrate temperature, which is clear from the mass spectra shown in FIGS. 14 and 15. That is, the grown film was measured using the RHEED pattern shown in FIG. 5, where the temperature of the cranking heater 17 of the gas cell 3 was 920°C, the temperature of the cracking heater 20 of the Knudsen cell 4 was 850°C, and the growth substrate temperature was 360°C. FIG. 14 shows the mass spectrometry spectrum of the grown film, and FIG. 15 shows the mass spectrometry spectrum of the grown film whose photoluminescence was measured in FIG. 13, which was doped with Ag at a growth substrate temperature of 250°C. From both figures, it can be seen that Gai in the grown film is much less in the latter.

As described above, by heating the molecular beams of group II and group VI with the Crab King heater, it is possible to give surface migration energy to the molecular beams on the growth substrate surface, thereby lowering the growth substrate temperature to the stoichiometric composition. ZnS, which is one of the n-VI group compound semiconductors, has high quality and can be set at a low temperature within the temperature range where single crystal growth is possible, thus enabling single crystal growth at a lower growth substrate temperature than before. This makes manufacturing possible.

Moreover, by heating the dopant molecular beam, energy for surface migration is also given to the dopant molecular beam, thereby making it possible to perform effective doping.

Although only ZnS was described in the above-mentioned embodiments, it goes without saying that the present invention can also be applied to the production of other n-VI group compound semisolid elements.

Furthermore, although the temperature of the growth substrate in the above embodiments varies depending on various conditions such as the beam intensity of the molecular beam, the configuration of the apparatus, and differences in distance, growth can be achieved by heating the molecular beam with a heater using the present invention. The fact that the temperature of the substrate can be set to a low temperature range within the temperature range where a stoichiometric composition can be achieved is shown in II-V by MBE.
It is very effective under various conditions in manufacturing Group I compound semiconductor devices.

〔Effect of the invention〕

As mentioned above, the molecular beams of group II and group VI are heated with a heater to provide energy for surface migration, and the growth substrate temperature is set to a low temperature within the temperature range that allows growth of a single crystal with a stoichiometric composition. According to the present invention, which is characterized in that the
This makes it possible to produce high-quality (1-2) group compound semiconductor devices with few lattice defects.

[Brief explanation of drawings]

Fig. 1 is a schematic diagram of an apparatus showing an embodiment of the present invention, Fig. 2 is a sectional view of the main part of a gas cell, Fig. 3 is a sectional view of the main part of a Knudsen cell, and Figs. 4 and 5 are respectively Substrate temperature 310℃
, 360°C, the Knudsen cell cracking heater temperature is 850°C, and the gas cell cranking heater temperature is 920°C.
The photos of the D pattern, Figures 6 to 8, show ZnS growth when the growth substrate temperature was 220°C, 250°C, and 270°C, and the Knudsen cell cranking heater was 900°C, and the gas cell cranking heater was 980°C. Photographs of each RHEED pattern of the membrane, Figure 9 is R in Figure 7 above.
Figure 10 is a graph of X-ray diffraction of the grown film when a HEED pattern is taken, and the growth substrate temperature is 220℃, 250℃,
A diagram showing the proportion of Zn in ZnS grown at three points at 70°C, Figure 11 is a diagram showing photoluminescence when ZnS is doped with Ga, and Figure 12 is a diagram showing the proportion of Zn in ZnS grown at 70°C.
Figure 13 is a diagram showing the photoluminescence when ZnS is doped with Ag, and Figure 14 is a diagram showing the results of measuring the resistivity of the grown film against temperature in a Knudsen cell containing ZnS. Figure 15 shows the mass spectrometry spectrum of the grown film whose RHEED pattern was measured.
It is a figure which shows the mass spectrometry spectrum of the grown film which measured the photoluminescence of a figure. 3------1.--Gas cell 4, 5-Knudsen cell 6.--1--Growth substrate 17.20--Cranking heater 1st! l 2nd figure 4th factor cycle 5 figure 9th figure -→20 (deg,) Hato 6 = Tsuji 7th school 8 Great factor 10th factor 1 group fall (°C) 11th prisoner - + photon energy (ev)th Fig. 12 Cta cell diameter &('C) Fig. 13 Cta cell length (nm) 1) Hoton energy (eVl compilation 14
Figure Mas5Nu+? Iber (atomic mass
ur+1ts)'lA15UA -1111 Mass NIJJylber (&
torn:c mtts ur+1tx) Main procedural document (method) % formula % 1. Indication of the case 1985 Patent Application No. 72.093 2. Name of the invention Method for manufacturing a II-VI group compound semiconductor device 3. Amendment May 7, 1985 (Shipping date: May 27, 1986) 5. Subject of amendment 1'). one! 6. Contents of correction (1) On page 11, line 10 of the specification, the phrase "photo of the RHEED pattern of the ZnS grown film at that time" was replaced with "a reciprocal lattice image of the crystal structure of the ZnS grown film at A photo of the RHEED pattern shown, corrected. (2) r- on page 11, line 14 to line 15 of the specification
=Photographs of each RHEED pattern of a ZnS grown film,'' is replaced by ``Photographs of a RHEED pattern showing a reciprocal lattice image of the crystal structure of each ZnS grown film.''
I will correct it.

Claims (1)

[Claims] In a method for manufacturing II-VI group compound semiconductor devices using the molecular beam epitaxial method, group II and group VI molecular beams are heated with a heater, the heating converts the molecular beams into high-temperature molecular beams with high energy, and the growth substrate is heated. 1. A method for manufacturing a II-VI compound semiconductor device, characterized in that the temperature is set in a low temperature range in which growth of a single crystal with a stoichiometric composition is possible.