DEVELOPMENT OF SOLID STATE IMAGING DETECTOR FOR HIGH ENERGY FLUX

用远程极性增强化学气相沉积（RPE-CVD）方法在砷化镓GaAs（100）衬底上外延生长了ZnSe、ZnTe、CdSeE和CdTe薄膜。以二乙基锌、二甲基镉和二乙基碲为源材料，利用射频感应耦合等离子体产生氢自由基。用自由基辅助MOCVD技术，在0.2Torr的低压下，在半绝缘GaAs衬底上外延生长了厚度约300 nm的n型和p型CdTe薄膜。以正丁基碘为掺杂剂前体，进行气相碘掺杂，获得n型导电性。在未掺杂的CdTe外延层表面蒸镀一层薄的（~ 30 nm）碱金属化合物（如NaTe）来实现p型掺杂。利用这种技术，在本征CdTe衬底（电阻率大于108 Ω cm）上生长p型和n型CdTe层，从而形成p-i-n结构。研究了探测器的性能，主要是暗电流-电压特性和不同光子能量下的X射线光电流，在研究方法上，我们发明了II-VI族化合物半导体的准分子激光掺杂技术。该技术对于实际的器件制造是非常有希望的。

ZnSe, ZnTe, CdSeE and CdTe thin films have deen epitaxially qrowm on gallium arsenide GaAs (100) substrates by the remote polasma enhanced chemical vapor deposition (RPE-CVD). Diethyl zinc, dimethyl cadmium and diethyl tellurium were used as source materials and hydrogen radicals generated by rf induction coupled plasma were introduced into the reaction chamber. Heteroepitaxial growth on GaAs substrate were fairly well obtained in single crystal phase.n-type and p-type CdTe were studied on the layrs (thickness around 300 nm) grown epitaxially on semiinsulating GaAs substrate by radical assisted MOCVD technique working at a low pressure of 0.2 Torr. Gas phase iodine doping to obtaine n-type conductivity was carried by utilizing n-butyliodine as a dopant precursor. p-type doping was achieved by evaporating a thin layr (-30nm) of alkaline metal compounds such as NaTe on the surface of the undoped CdTe epitaxial layrs were thus obtained. Using this technique, p-and n-type CdTe layrs were grown on the intrinsic CdTe substrate (resistivity larger than 108 ohm cm) so as to form the p-i-n structure. Performance of detector, mainly dark current-voltage characteristics and x-ray photocurrent at different photon energies, have been studied.on the research way, we have invented the technique of excimer laser doping for II-VI compound semiconductor. This techniques are very promissing for actual device fabrication.