热交换法中氦气循环利用的装置和方法研究

Research on the Device and Method of Helium Recycling in Heat Exchange Method

可用于LED衬底的材料主要有硅、碳化硅、蓝宝石、氮化镓等。由于硅单晶和氮化镓晶格匹配太差无法商业化应用;碳化硅单晶成本价格较高,目前市价约是蓝宝石晶体的5倍以上;氮化镓单晶制备更困难,虽然同质外延质量最好,但价格是蓝宝石晶体的数百倍。综上所述,预计未来30年内,蓝宝石单晶还是LED衬底材料的理想选择。目前,蓝宝石的生长方法主要有提拉法(Cz)、导模法(EFG)、泡生法(Ky)、热交换法(HEM)等。本文介绍了各种蓝宝石长晶方法,并对其优缺点进行了分析。通过分析热交换法在生长大尺寸无缺陷晶体具有明显优势,结合热交换法原理开发了氦气管道,为降低热交换法生长蓝宝石成本提供了一种可行装置和方法。

The materials that can be used as LED substrates mainly include silicon,silicon carbide,sapphire,gallium nitride,etc.Due to poor lattice matching between silicon single crystal and gallium nitride,it cannot be commercially applied.The cost and price of silicon carbide single crystals are relatively high,and the current market price is about 5 times higher than that of sapphire crystals.The preparation of gallium nitride single crystals is more difficult.Although homogeneous epitaxy has the best quality,its price is hundreds of times higher than that of sapphire crystals.In summary,it is expected that sapphire single crystals will remain the ideal choice for LED substrate materials in the next 30 years.At present,the main growth methods for sapphire include Cz,EFG,Ky,and HEM.This article introduces various methods for sapphire crystal growth and analyzes their advantages and disadvantages.By analyzing the significant advantages of heat exchange method in growing large-sized defect free crystals and combining the principle of heat exchange method,a helium gas pipeline has been developed,providing a feasible device and method for reducing the cost of heat exchange method in growing sapphire.