EXCIMER LASER DOPING FOR WIDE-GAP SEMICONDUCTORS

宽禁带II-VI半导体的P型掺杂是器件制作中与金属电极形成欧姆接触的关键技术。利用含有掺杂原子的碱金属化合物K2S、Na2Se或Na2Te，对ZnSe和CdTe进行了准分子激光掺杂实验。电性能对该处理的影响主要是通过霍尔测量来测量的。用Na2Te作为掺杂原子的化合物激光掺杂后，ZnSe的电阻率从105降到10-2欧姆cm，荷利载流子浓度增加到4.8×1019 cm-3。还研究了CdTe p-i-n二极管中p型欧姆接触的形成。我们将这一技术进一步扩展到具有空间图案的掺杂。用条形探测器图案演示了空间图案化的掺杂。这些掺杂技术有望制备出集成的CdTe二维成像系统。由于其高吸收系数、大禁带宽度、良好的空穴迁移率寿命积以及在正常大气条件下的稳定性，使其成为一种在固态高能X射线和伽马射线成像系统中有应用前景的半导体材料。这项技术将对集成伽马射线探测器的制造至关重要。

p-type doping of wide band gap II-VI semiconductors is a key technology to form the ohmic contact with metal electrodes in device fabrications. Using an alkaline metal compound such as K2S, Na2Se or Na2Te which contains dopant atoms, excimer laser doping experiment were carried out for ZnSe and CdTe. Influence of the electrical properties on this treatment was mainly measured by mean of the Hall measurement. The resistivity of ZnSe drastically decreased from 105 to 10-2 ohm cm and the value of holwe carrier concentration increased up to 4.8 x 1019 cm-3.For CdTe, also resistivity decreased from 105 to 10-1 ohm cm by laser doping method using Na2Te as a compound including dopant atoms. Formation of p-type ohmic contact in CdTe p-i-n diode was also investigated. We have further extended this technique for doping with spatial pattern. The spatially patterned doping is demonstrated with strip detector patterns. These doping techniques are promising for the fabrication of integrated CdTe two-demensional imaging system.CdTe is an attractive semiconductor material for applications in solid-state high energy X-ray and gamma ray imaging systems because of its high absorption coefficient, large bandgap, good mobility life time product of holes and stability at normal atmospheric conditions. This technique will be essential for integrated gamma ray detector fabrications.