红外光热吸收成像技术在碲锌镉材料检测中的应用

Inspection of CdZnTe materials by infrared photo-thermal absorption imaging

红外光热吸收效应作为一种无损伤非接触的检测技术已经被广泛用于硅等半导体材料中的微缺陷表征分析.采用光热吸收技术对碲锌镉晶体中的缺陷进行扫描成像分析时发现了一种连续性的光貌相条纹并对这些条纹的形成机理进行了研究.研究表明碲锌镉晶体中的这种连续性条纹源自于光热测试系统中入射光的干涉这种干涉和入射光参数、测试样品的厚度、禁带宽度以及热导率等材料特性密切相关.最后实验通过优化红外光热吸收测量系统获得了碲锌镉材料中的微缺陷结构及其在样品深度方向的三维分布图像.

Infrared photo-thermal absorption effect was used extensively in detecting the micro-defects in semiconductor materials ( silicon wafers) as a nondestructive and non-contact technology. This effect was adopted initially to detect the structural characteristic of the defects in CdZnTe ( CZT) crystal and images with obvious coherent fringes were obtained,which were investigated systemically. It was confirmed that the coherent fringes of the Infrared photo-thermal absorption images of CZT wafers come from the interference of incident light relative to parameters of incident light,wafer thickness,thermal conductivity and band gap of materials. Finally,the micro-defects of CZT materials and their distribution along depth direction were obtained by optimizing the test conditions.