Cd1-yZnyTe的Zn组分面分布及均匀性控制

随着HgCdTe红外探测器尺寸规模的扩大,晶格匹配的Cd1-yZnyTe衬底组份均匀性越来越受到重视。由于在CdZnTe晶体中Zn的分凝系数大于1,晶片中Zn组分分布不均匀,从而使HgCdTe外延薄膜不同区域因晶格失配而产生位错的情况不同, 精确测量CdZnTe衬底的Zn组分及其均匀性是十分必要的。高分辨率X射线衍射是精确测量晶格常数和Zn组分的有效方法之一,但不适合常规面分布测定,而采用红外透射光谱法则能够在短时间内及实验容许的误差范围内快速获得CdZnTe中Zn组份的分布。另外,对锭条上不同方位的晶片进行径向和横向面分布红外透射光谱测量,可为组份均匀性控制提供依据。

Zn Concentration Mapping and Uniformity Control of Cd1-yZnyTe Crystal

The Zn concentration uniformity of lattice matched Cd1-yZnyTe substrates is becoming more and more important with the increasement of the size of HgCdTe IR detectors. As the Zn distribution coefficient is greater than 1 in Cd1-yZnyTe crystal and the Zn concentration distribution is asymmetric, the dislocation of epitaxially grown HgCdTe layers caused by lattice misfit is different. So, the measurement of the accurate Zn concentration of Cd1-yZnyTe crystal is very critical. X-ray diffraction is one of the effective ways to measure accurate lattice constant and Zn concentration, but it is not suitable for large area mapping. The Zn concentration of CdZnTe crystal can be obtained by IR transmission spectrum in short time and precision. Also the radial and axis Zn concentration distribution measurement by infrared transmission spectroscopy offer important references for concentration uniformity control.