碲镉汞多色红外焦平面探测芯片

文章从芯片结构、晶格匹配和PN结性能三个方面对碲镉汞多色焦平面探测芯片技术进行了探讨,结果显示在三种主要的双色探测芯片结构中,单电极和环孔工艺的双色芯片技术相对比较成熟,高难度的刻蚀技术以及所引起的表面反型是制约双电极或多电极多色探测芯片技术发展的主要因素,而环孔技术在发展多色探测芯片方面则有其独到之处,随着探测波段的增加,其工艺难度并没有质的变化。多色探测芯片不同外延层之间的晶格失配以及和Si基衬底之间热失配也是必须加以考虑和解决的一个问题,在现阶段, Si基直接外延、大面积碲锌镉材料和ZnCdTe /Si复合衬底技术并举仍将是明智的选择。在PN结方面,二代焦平面的成结技术在多色器件的宽带结上尚未能够实现,刻蚀反型和深台面侧面钝化的困难依然存在,这些均制约着器件性能的提高,另外,多色芯片的结构和表面加工工艺也影响着探测芯片的光通量利用率和量子效率。

HgCdTe Multi-color Infrared Focal Plane Arrays

The architecture,lattice match and PN junction of HgCdTe multicolor focal plane arrays(FPA) have been studied.The dual-color detectors with single electrode and loophole technology have demonstrated better performance compared with other architectures of the detectors limited by micro-fabrication technology.The loophole technology has a merit that the complexity of technology doesn't obviously increase with the increase of waveband numbers.The lattice mismatch between different composition HgCdTe layers and thermal mismatch between the epilayer and Si substrate should be considered for the longwave detectors.The techniques of Si-based HgCdTe epitaxy,large size of CdZnTe and complex substrate ZnCdTe/Si will be developed simultaneously at present.In the aspect of PN junction,there are some difficulties to apply the mature technology of second generation HgCdTe FPA to wide band PN junction of multicolor FPA.The problems,such as the electrical reversion caused by the dry etching and lateral passivation,which have great influence on the performance of PN junction,also exist.The use efficiency of light flux and quantum efficiency are also limited by the device architecture and micro-fabrication technology.