DEVELOPMENT OF INTEGRADED IMAGING DETECTOR FOR HIGH ENERGY FLUX

采用远程等离子体增强化学气相沉积（RPE-CVD）技术在砷化镓GaAs（100）衬底和CdTe衬底上外延生长了CdTe、CdZnTe、CdSeTe薄膜。以二乙基锌、二甲基镉和二乙基碲为原料，将射频感应耦合等离子体产生的氢自由基引入反应室。异质外延和同质外延生长和杂质掺杂在探测器器件的制造中得到了很好的效果。通过在高电阻率周p型晶片的一侧生长碘掺杂外延层，在另一侧放置金电极，以新的p-i-n设计制作了CdTe核辐射探测器。该器件具有良好的整流性能，具有非常低的反向偏置漏电流，在室温（25℃）下，施加电压为250V时，通常为60 pA/mm2。该探测器表现出优异的核辐射探测性能。在室温下，探测器在59.5、122和662 keV伽马峰处的能量分辨率分别为1.42、1.7和4.2 keV。研究了一种新型的p-i-n二极管结构大面积条纹探测器的制作工艺。探测器是在高电阻率CdTe晶片的一侧生长n-CdTe层，另一侧利用准分子激光的杂质掺杂技术制成精细的p型条带。初步结果表明，该方法在带状探测器的制作上是非常有用的，并为大面积成像系统的发展铺平了道路。

CdTe, CdZnTe, CdSeTe thin films have been epitaxially grown on gallium arsenide GaAs(100) substrates and CdTe substrates by the remote plasma 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. Hetero- and Homo- epitaxial growths and impurity doping were fairly well obtained in for the fabrication of the detector devices.CdTe nuclear radiation detectors were fabricated in a new p-i-n design by growing an iodine doped epitaxial layer on one side of the high resistivity week-p-type crystal wafer and a gold electrode was placed on the opposite side. The fabricated device showed a good rectification property with a very low reverse biased leakage current, typically 60 pA/mm2 at room temperature(25C) for an applied voltage 250V. The detectors exhibited excellent nuclear radiation detector properties. The spectral responses of the detector showed an energy resolution 1.42, 1.7 and 4.2 keV FWHM at 59.5, 122 and 662 keV gamma peak, respectively at room temperature.A new fabrication processes for the large area stripe detectors in a p-i-n diode configuration was studied. The detector has been constracted by growing n-CdTe layer on one side of the high resistivity CdTe crystal wafer and utilizing the excimer laser based impurity doping technique on the other side to make the fine p-type strips. The preliminary result showed this approach is very useful on the strip detector fabrication and paves a way for the development of large area imaging system.