CN104213195A

CN104213195A - Low-temperature PVT method for controlling single crystal growth wrappage defect

Info

Publication number: CN104213195A
Application number: CN201410492711.5A
Authority: CN
Inventors: 程红娟; 司华青; 李璐杰; 徐永宽; 练小正; 张志鹏
Original assignee: CETC 46 Research Institute
Current assignee: CETC 46 Research Institute
Priority date: 2014-09-24
Filing date: 2014-09-24
Publication date: 2014-12-17
Anticipated expiration: 2034-09-24
Also published as: CN104213195B

Abstract

The invention relates to a low-temperature PVT method for controlling the single crystal growth wrappage defect. The method comprises the following steps of adopting a PVT single crystal furnace, adopting relatively-high in-cavity air pressure ranging from 800 mbar to1000 mbar at an early growth single crystal stage for 2-6 hours and keeping large temperature gradient at the seed crystal position to range from 15 DEG C to 30 DEG C so as to control the single crystal growth rate to range from 0.05 mm/h to 0.15 mm/h, gradually reducing the air pressure 100-400 mbar and the single crystal temperature gradient at the seed crystal position by 2 DEG C to 10 DEG C so as to improve the growth rate of high-quality crystal to range from 0.2 mm/h to 0.5 mm/h after the early growth stage for 2-6 hours is completed, rapidly increasing pressure intensity to range from 900 mbar to1100 mbar after the growth is completed, and further reducing the temperature gradient at the seed crystal position by 1 DEG C to 2 DEG C. The low-temperature PVT method has the technical advantages of controlling the wrappage defect to be within a small range and improving the available crystal size and crystal quality.

Description

A kind of low temperature PVT controls the method for single crystal growing wrap defect

Technical field

The present invention relates to a kind of low temperature PVT and control method for monocrystal growth, particularly a kind of method of controlling low temperature PVT bulk growth wrap defect.

Background technology

II-VI compound semiconductor has direct transition band structure, and with its distinctive light transfer characteristic, at aspects such as solid luminescence, laser, infrared, piezoelectric effect and photosensors, is widely used.But because II-VI compounds of group generally has, fusing point is high, growth air pressure high, and liquid phase method growth is higher to equipment requirements.Adopt subliming method (PVT) only to need lower temperature (1100 ℃ following), therefore, PVT method becomes the important method of preparation II-VI compounds of group.But in body monocrystal material PVT method process of growth, tend to produce some macroscopical defects, as wrap etc., its diameter is in micron dimension, length even can reach a millimeter magnitude, and the quality of the crystal particularly defect such as wrap will have a strong impact on the used volume of crystal and the performance of device and stability, therefore in high quality bulk single crystal preparation process, often need by certain technique means, defect to be suppressed, at utmost reduce the impact of defect.

Summary of the invention

The II-VI compounds of group single crystal preparation research of carrying out both at home and abroad is at present considerably less, shape characteristic to its wrap defect, mechanism of production and control device research are less, the present invention is by the adjustment to growth temperature and pressure in bulk growth process, control generation and the distribution range of wrap defect, improve crystal mass, concrete technical scheme is, a kind of low temperature PVT controls the method for single crystal growing wrap defect, it is the bulk growth method based on there being seed crystal PVT method, step is as follows: 1), adopt PVT single crystal growing furnace, by raw material, seed crystal, substrate is put into specified location, raw material and seed crystal are determined by the II-VI family monocrystalline that will grow, substrate adopts sapphire conventionally, the higher polished section of thermostability such as quartz, 2), 2 ~ 6 hours of single crystal growing initial stage, assemble under hot environment in gap between seed crystal and substrate, form a large amount of wrap defects, now adopt relatively high cavity internal gas pressure 800 ~ 1000mbar, and to keep the larger thermograde in seed crystal place be 15 ~ 30 ℃, so that the growth velocity of monocrystalline was controlled in 0.05 ~ 0.15mm/ hour, and increase, wrap defect produces and mobile speed, impels wrap defect to shift out rapidly crystal, 3), after end in 2 ~ 6 hours of early growth period, reduce gradually air pressure 100 ~ 400mbar, and reduce by 2 ~ 10 ℃ of the thermogrades of seed crystal place monocrystalline, to increase growth velocity to the 0.2 ~ 0.5mm/ hour of high quality crystal, suppress the movement of wrap defect, it is trapped near seed crystal, 4), the growth pressure 900 ~ 1100mbar that increases sharply after finishing, further reduce by 0 ~ 2 ℃ of seed crystal place thermograde, wrap defect is controlled in less scope, 5), program end of run, take out growth tube and supporting structure, can obtain the concentrated high quality II-VI family monocrystalline of wrap defect distribution.

Technological merit of the present invention is the adjustment by growth technique, and inclusion defect in single crystal is trapped in apart from the nearer layer-shaped area of seed crystal, suppresses the big area diffusion of defect, has improved crystal available volume and crystal mass.

Accompanying drawing explanation

Fig. 1 is that single crystal growing defect of the present invention suppresses mobile schematic diagram.

Fig. 2 is that the present invention has seed body monocrystalline PVT growth schematic diagram.

Specific embodiments

PVT legal system is example for the method for CdS monocrystalline, and as shown in Figure 1, 2, CdS single crystal growing adopts five warm area PVT crystal growing furnaces, and the warm area from feed end to substrate terminal is respectively one to five warm area, take sapphire polished section as substrate.

1), raw material 1, seed crystal 2, substrate 3 are put into specified location, raw material 1 employing CdS powder, seed crystal 2 employing Ф 30mm CdS monocrystalline, the quartzy polished section of substrate 3 employing;

2), crystal early growth period is called for short stage I, the warm area in crystal growth is set to 1055 ℃, 1030 ℃, 990 ℃, raw material 1st district, 985 ℃, 970 ℃, seed crystal district, pressure is set as 600mbar, first growth cycle is set as 3 hours;

3) be called for short stage II the vegetative period, after crystal early growth period finishes, warm area is adjusted into 1055 ℃, places 1030 ℃, 990 ℃, raw material 1st district, 985 ℃, 985 ℃, seed crystal district, pressure is set as 200mbar, and constant temperature 20 ~ 200h keeps crystal growth;

4), after crystal finishes vegetative period, be called for short stage III, operation cooling process also guarantees that seed crystal place warm area temperature is identical, and pressure is set as 1000mbar, is reduced to room temperature;

5), treat program end of run, take out growth tube 4, can obtain the concentrated high quality CdS monocrystalline 6 of defect distribution.

Claims

1. low temperature PVT controls a method for single crystal growing wrap defect, is the bulk growth method based on there being seed crystal PVT method, and step is as follows:

1), adopt PVT single crystal growing furnace, raw material (1), seed crystal (2), substrate (3) are put into specified location, raw material (1) and seed crystal (2) are determined by the II-VI family monocrystalline that will grow, and substrate (3) adopts the higher polished section of thermostability such as sapphire, quartz conventionally;

2), monocrystalline (6) early growth period 2 ~ 6 hours, assemble under hot environment in gap between seed crystal (2) and substrate (3), form a large amount of wrap defects (7), now adopt relatively high cavity internal gas pressure 800 ~ 1000mbar, and to keep seed crystal (2) to locate larger thermograde be 15 ~ 30 ℃, so that the growth velocity of monocrystalline (6) was controlled in 0.05 ~ 0.15mm/ hour, and increase, wrap defect (7) produces and mobile speed, impels wrap defect (7) to shift out rapidly crystal;

3), the vegetative period after early growth period finishes for 2 ~ 6 hours, reduce gradually air pressure 100 ~ 400mbar, and reduce by 2 ~ 10 ℃ of the thermogrades that seed crystal (2) is located monocrystalline (6), to increase growth velocity to the 0.2 ~ 0.5mm/ hour of high quality crystal, suppress the movement of wrap defect (7), it is trapped near seed crystal (2);

4), vegetative period the pressure 900 ~ 1100mbar that increases sharply after finishing, further reduce seed crystal (2) and locate 0 ~ 2 ℃ of thermograde, wrap defect (7) is controlled in less scope;

5), program end of run, take out growth tube (4) and supporting structure (5), can obtain the high quality II-VI family monocrystalline (6) that wrap defect (7) distributes concentrated.