Laser Doping Process for wide-bandgap compound semiconductors

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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.