CN205275775U

CN205275775U - Vertical pulling method is grown and is hanged down thermal field structure of dislocation single crystal

Info

Publication number: CN205275775U
Application number: CN201520864558.4U
Authority: CN
Inventors: 黎建明; 冯德伸; 高欢欢; 张路; 王霈文
Original assignee: YOUYAN PHOTOELECTRIC NEW MATERIAL CO Ltd
Current assignee: Grinm Electro Optic Materials Co ltd; Grinm Guojing Advanced Materials Co ltd; Youyan Technology Group Co ltd
Priority date: 2015-11-03
Filing date: 2015-11-03
Publication date: 2016-06-01
Anticipated expiration: 2025-11-03

Abstract

The utility model discloses a vertical pulling method is grown and is hanged down thermal field structure of dislocation single crystal. This thermal field structure includes along the primary heater of single crystal growing furnace oven setting and sets up at the end of single crystal growing furnace stove bottom heater. The primary heater is the straight section of thick bamboo structure of thin gradual change type of favoring down. The technology that adopts the low dislocation single crystal of this thermal field structure growth includes at least: (1 )Select the dislocation -free single crystal as the seed crystal, at the crystal growth in -process, the intensificationization material reaches target temperature, (2 )Stabilize the stable back of a period thermal field with the fuse -element, look for the seeding temperature, in the direct shouldering in back in 1 hour of this seeding temperature spot seeding, (3 )Grow, finish up, cool off to the room temperature through the automatic control constant diameter, accomplish low dislocation crystal growth. Adopt the utility model discloses a low temperature gradient of temperature gradient, increase that the thermal field structure can reduce in the thermal field is regional, crystal growth technology in the low temperature gradient thermal field of combination can extend and hang down the effective length of dislocation crystal.

Description

The thermal field structure of Grown by CZ Method low dislocation monocrystalline

Technical field

This utility model relates to the thermal field structure of a kind of Grown by CZ Method low dislocation monocrystalline, belongs to low dislocation technical field of single crystal growth.

Background technology

Vertical pulling method is a kind of important method for monocrystal growth, and the method observable, crystal growth cycles are short, and efficiency is high, cost is low, can obtain the high quality single crystal of major diameter. In vertical pulling method low dislocation crystal growth, thermograde is the key factor affecting dislocation density. Straight barrel type list heater structure is as it is shown in figure 1, heater 1 is straight barrel type, and upper and lower thickness is identical. In this thermal field, thermograde changes greatly, and heater edge thermograde is big, and low-temperature gradient region is less. Such thermal field grows low dislocation monocrystalline and there is reduction dislocation density difficulty, the problems such as length is short, and efficiency is low.

Utility model content

The purpose of this utility model is in that to provide the thermal field structure of a kind of Grown by CZ Method low dislocation monocrystalline, and the thermograde to solve the growth thermal field system existence of existing low dislocation is big, the problems such as low-temperature gradient regional extent is little.

For achieving the above object, this utility model is by the following technical solutions:

The thermal field structure of a kind of Grown by CZ Method low dislocation monocrystalline, this thermal field structure includes the primary heater arranged along single crystal growing furnace furnace wall and the end heater being arranged on single crystal growing furnace furnace bottom.

Wherein, described primary heater is the gradation type tubular construction of upper-thin-lower-thick. Described primary heater is downwards a constant thickness from 1/2 place of its height, upwards thinning successively; Upper the thinnest along place, its thickness is the 2/3-5/6 of constant thickness; End heater is the graphite resistance heater of flat round structure.

Described primary heater is, with power supply and the control system of end heater, the autonomous system being connected with electrical source of power, and therefore the power of described primary heater and end heater all can individually regulate.

Adopt the growth technique of described thermal field structure growth low dislocation monocrystalline, at least comprise the following steps:

(1) selecting dislocation-free single crystal as seed crystal, in crystal growing process, temperature increasing for melting materials reaches target temperature;

(2) after being ensured, thermal field is stable Melt Stability a period of time, adopting seed crystal and melt welding, when observing seed crystal with melt contacts, the method for solid liquid interface variable condition, finds suitable seeding temperature, and seeding adopts Automatic Program cooling shouldering after 1 hour.

(3) through automatically controlling isodiametric growth, finish up, being cooled to room temperature, low dislocation crystal growth is completed.

In described step (2), the method finding suitable seeding temperature is: solid liquid interface variable condition when observing seed crystal with melt contacts, when seed crystal is grown up with melt weld crystal in 5 minutes is inconspicuous or reduces, with this fusion temp for seeding temperature.

The beneficial effects of the utility model are:

Thermal field structure of the present utility model adds end heater on existing single heater (primary heater) architecture basics, the gradation type tubular resistance heater being shaped as upper-thin-lower-thick of primary heater, reduces the thermograde in thermal field, increases low-temperature gradient region; In conjunction with crystal growth technique in low-temperature gradient thermal field, it is possible to lengthen the effective length of low dislocation crystal.

Accompanying drawing explanation

Fig. 1 is the structural representation of single heater.

Fig. 2 is this double-heater structural representation.

Fig. 3 is different thermal field system Axial Temperature Distribution schematic diagrams.

Detailed description of the invention

Below in conjunction with the drawings and specific embodiments, this utility model is specifically described.

As in figure 2 it is shown, the thermal field structure of Grown by CZ Method low dislocation monocrystalline of the present utility model includes the primary heater 2 arranged along single crystal growing furnace furnace wall and the end heater 3 being arranged on single crystal growing furnace furnace bottom. Wherein, primary heater 2 top is the thinnest, thickening gradually, the resistance heater of the gradation type straight tube structure of upper-thin-lower-thick. The power of primary heater 2 and end heater 3 all can individually regulate.

Thermal field structure of the present utility model is the double-heater structure of the resistance heater of the gradation type straight tube structure including upper-thin-lower-thick and end heater. As it is shown on figure 3, wherein solid line is existing single heater structure thermal field Axial Temperature Distribution, dotted line is double-heater structure thermal field Axial Temperature Distribution of the present utility model. In thermal field structure of the present utility model, the change of primary heater shape, reduce the thermograde on thermal field top; The addition of end heater improves the temperature bottom thermal field, reduces the thermograde of thermal field bottom, thus reducing thermal field integral gradient, and increases low-temperature gradient region, it is achieved that the low-temperature gradient on a large scale needed for long low dislocation crystal growth.

During crystal growth, crucible is placed in correct position, after heat temperature raising melting sources, regulates primary heater and stablize a period of time (being determined by weight of loading and material thermal conductivity etc.) with end heater power, it is thus achieved that stable low-temperature gradient thermal field; Then looking for suitable controlled seeding temperature, method is: solid liquid interface variable condition when observing seed crystal with melt contacts, when seed crystal is grown up with melt weld crystal in 5 minutes is inconspicuous or reduces, with this fusion temp for seeding temperature. The crystal growing process such as shouldering, isodiametric growth, ending, cooling are carried out after completing seeding under this fusion temp.

In crystal growth, seed crystal used is dislocation-free single crystal, in crystal growing process, after temperature increasing for melting materials reaches target temperature, for avoiding the thermal shock of seeding process, melt need to be stablized a period of time after (being determined by weight of loading and material thermal conductivity etc.) ensure that thermal field is stable, just start seeding, then directly shouldering, through automatically controlling isodiametric growth, finish up, be cooled to room temperature etc. and complete low dislocation crystal growth overall process; In this crystal growing process, adopt seed crystal and melt welding, the method for solid liquid interface variable condition when observing seed crystal with melt contacts, find the key that seeding temperature is low dislocation crystal growth. During due to crystal growth, seeding is to carry out after low-temperature gradient thermal field is stable, it is not necessary to long-time seeding process, saving the time, improving growth efficiency, thus saving cost.

Comparative example

In charge 40kg, 4 inches of low dislocation germanium single crystal thermal field systems, growing 4 inches of low dislocation germanium single crystals, adopt the straight barrel type structure graphite resistance list heater of diameter 450mm, long 650mm, power is about 45kw, near germanium fusing point 937 DEG C, it is low-temperature gradient scope that central region is about 180mm, the thermograde obtained is about 2k/cm, before seeding, heater power stablizes 2-5 hours, high bushing position (high-temperature gradient region) crystal pulling is adopted during seeding, low bushing position (low-temperature gradient region) position seeding, usual seeding speed is about 6mm/ hour, seeding length is about 200mm, eliminate the dislocation that thermal shock introduces, 30-40 hour consuming time, then industrial program controller able to programme is adopted to control primary heater power, turn 4-10 with crystalline substance per minute to turn, crucible turns 2-8 and turns, the speed of growth is about 2-6mm/ hour and carries out crystal growth, diameter 4 inches can be grown, long 150mm, dislocation density is about 3000cm^-2Germanium single crystal.

Embodiment

Changing the thermal field structure in comparative example 1 into thermal field structure of the present utility model, during material, primary heater power is about 42kw, end heater power is about 10kw, at this moment below edge about 1/4 length about 450mm scope is gone up at primary heater (diameter is identical with the single heater in comparative example 1 with length), near germanium fusing point 937 DEG C, obtainable thermograde is reduced to below 0.3k/cm, before seeding, heater power stablizes 6-10 hour, directly adopt seed crystal and melt welding at low bushing position (low-temperature gradient region), the method of solid liquid interface variable condition when observing seed crystal with melt contacts, find seeding temperature, then directly shouldering after seeding temperature place seeding about 1 hour, industrial program controller able to programme is adopted independently to control primary heater, end heater power, turn 4-10 with crystalline substance per minute to turn, crucible turns 2-8 and turns, the speed of growth is about 2-6mm/ hour and carries out crystal growth, diameter 4 inches can be obtained, long 200mm, dislocation density is less than 500cm^-2Dislocation-free germanium single crystal.

Claims

1. the thermal field structure of a Grown by CZ Method low dislocation monocrystalline, it is characterised in that this thermal field structure includes the primary heater arranged along single crystal growing furnace furnace wall and the end heater being arranged on single crystal growing furnace furnace bottom; Described primary heater is the gradation type straight tube structure of upper-thin-lower-thick; Described primary heater is downwards a constant thickness from 1/2 place of its height, upwards thinning successively; Upper the thinnest along place, its thickness is the 2/3-5/6 of constant thickness.

2. the thermal field structure of Grown by CZ Method low dislocation monocrystalline as claimed in claim 1, it is characterised in that heater of the described end is the graphite resistance heater of flat round structure.

3. the thermal field structure of Grown by CZ Method low dislocation monocrystalline as claimed in claim 1, it is characterised in that described primary heater is, with power supply and the control system of end heater, the autonomous system being connected with electrical source of power, and its power all can individually regulate.