Method and device for doping antimony element in heavily-doped antimony silicon single crystal

Abstract

The invention provides a method and a device for doping antimony element in heavily-doped antimony silicon single crystal. The doping device comprises a quartz outer cover and an inner material loading hopper, the inner material loading hopper is made of a graphite substrate plated with a silicon carbide coating, and the inner material loading hopper is arranged in the quartz outer cover. The hopper cover of the hopper is a counterweight cover, and the lower part of the hopper body is a slender cylinder. When in use, the doping device is placed in the single crystal furnace through the connecting hole on the quartz outer cover system, the slender cylindrical part at the lower part of the material loading funnel is immersed into a silicon melt, and the counterweight cover of the funnel slides down along the guide rail until all the antimony elementary substances enter the molten silicon as the antimony element in the funnel is continuously doped into the silicon melt and the amount of the antimony element in the funnel is reduced. The slender cylindrical part of the hopper body is always positioned in the silicon melt in the whole doping process, so that the loss caused by the fact that antimony steam is blown away by argon flow in the furnace is avoided. The doping efficiency of the antimony element is increased to 90%, and the situation that the yield is greatly reduced due to doping failure of the heavily-doped antimony silicon single crystal is avoided.

Description

technical field [0001] The invention relates to the technical field of preparation of silicon single crystals, in particular to a method and a doping device for doping antimony elements in heavily doped antimony silicon single crystals. Background technique [0002] Heavy-doped silicon single wafer is an ideal substrate material for the preparation of diodes, microwave power devices, CMOS circuits, etc. Among the many doping elements, antimony has a small diffusion coefficient, and the reverse diffusion of the epitaxial layer will not be formed in the subsequent epitaxy high temperature process, showing the advantage of a steep gradient. + The best substrate for silicon epitaxial wafers. Domestic research on heavy antimony-doped silicon single crystal has always been attached great importance. [0003] Domestic researches mostly focus on oxygen precipitation, control of micro-defects in heavily doped antimony single crystals, and changes in oxygen content in heavily doped ...

AI Technical Summary

Problems solved by technology

There are mainly the following defects, first: due to the evaporation constant of antimony 7×10 -2 cm / s, very volatile, during the doping process, the antimony melt starts to volatilize when it starts to drop into the molten silicon, the longer the doping time, the greater the volatilization of antimony; due to the high viscosity of antimony melt , the speed of dripping down is very slow. Although the doping time is not mentioned, the actual doping time is very long, that is to say, the volatilization of antimony is very large. Similarly, if the lower mouth of the funnel extends into Due to the high viscosity of the antimony melt inside the silicon melt, the downward flow rate is very slow, and it is difficult to achieve heavy doping of antimony elements; second: at the moment when the antimony melt enters the silicon melt, due to the interaction between the antimony melt and the silicon melt The temperature difference will cause splashing of molten silicon and antimony melt, resulting in the phenomenon of funnel bursting in the quartz funnel

[0007] In summary, in the doping methods of the prior art, there are problems of long doping time, serious volatilization of antimony, and low doping efficiency.

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