EXCIMER LASER DOPING FOR WIDE-GAP SEMICONDUCTORS

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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.