Laser Doping Process for wide-bandgap compound semiconductors

研究了宽禁带化合物半导体的激光掺杂加工技术。特别是对于CdTe、ZnO、ZnTe等II-VI类化合物半导体，由于其具有自补偿效应而难以大量掺杂，而由于II-VI类晶体的硬度较低，难以采用热扩散和离子注入等传统方法对硅进行掺杂。激光掺杂工艺是一种低温加工技术。该过程只有两个简单的步骤，即在样品表面沉积掺杂源，在高压环境下在样品表面照射准分子激光脉冲（20nS）。在该技术中，发现激光束强度受掺杂条件的影响很大。该装置安装的激光束均质器系统使大面积均匀掺杂成为可能，并清楚地了解了激光强度的依赖性。然后，我们可以获得重掺杂，该技术可以应用于制作光电器件。在CdTe样品中，通过激光模式掺杂和激光磨损加工可以制作集成伽马射线成像装置，在p型ZnO中获得了10^<19> cm^<-3>的高空穴浓度。

Laser doping processing technique has been investigated for wide-bandgap compound semiconductors. Specially, the method has been researched for II-VI compound semiconductors such as CdTe, ZnO, ZnTe which are difficult for heavily doping because these have self-compensation effects, and it is difficult to apply conventional method for silicon such as thermal diffusion and ion implantation since the II-VI crystals are not so hard. The laser doping process is low temperature processing technique. The process have has only simple two steps, i) a dopant source was deposited on sample surface, and ii) an excimer laser pulse (20nS) was irradiated on its surface under the high-pressure ambient. In this technique, it was found that the laser beam intensity was strongly effect for doping conditions. The uniform doping in large area have became possible by laser beam homoginizer system, which installed by this Gran-in-Aid, and it was clearly understand laser intensity dependences. Then, we could obtain heavily doped and this technique could be applied to made opto-electorical device. In CdTe samples, integrated gamma-ray imaging device could be fabricated by laser pattern-doping and laser abrasion processing, and high hole concentration of 10^<19> cm^<-3> was obtained in p-type ZnO.