长波碲镉汞p型掺杂机理和器件低频噪声研究进展

针对长波碲镉汞红外焦平面器件发展的需求,本文分别从材料的p型掺杂机理和器件的低频噪声两个方面概述了相关的研究进展.(1)理论上修正了经典的As掺杂p型激活模型,并提出了新的激活模型,即以复合缺陷(Te_Hg-V_Hg)主导下的As迁移,最终形成AsTe2复合体而表现为p型.(2)理论上解释了Au原子在碲镉汞材料中呈现快扩散特性,是由间隙扩散机制所导致的,提出了通过Au杂质与Hg空位的相互作用,以Hg空位作为介质来调控Au杂质浓度分布的方法,可以实现可控的p型掺杂,并被实验所验证.(3)搭建了高灵敏低频噪声的测试系统,结合器件性能仿真,构建了低频噪声的分析评价方法,并研究了长波碲镉汞器件低频噪声与器件暗电流之间的关联性.

Research progress on p-type doping mechanism and low frequency noise of long wave HgCdTe devices

In order to meet the needs of the development of long wave HgCdTe infrared focal plane devices,this paper summarizes the related research progress from two aspects:the p-type doping mechanism of materials and the low-frequency noise of devices.It includes:(1)the classical p-type activation model of as doping is modified theoretically,and a new activation model is proposed,that is,as migration dominated by composite defect Te_Hg-V_Hg leads to the formation of AsTe2 complex,which shows p-type.(2)It is theoretically explained that the fast diffusion characteristics of Au doped HgCdTe are caused by the interstitial diffusion mechanism;a method is proposed to control the spatial distribution of Au impurities through the interaction between Au impurities and Hg vacancies,which can realize controllable p-type doping and is verified by experiments.(3)A high sensitivity and low frequency noise test system is built.Combined with the numerical calculation model,the evaluation method of low-frequency noise is established.At the same time,the origin of low-frequency noise of long wave HgCdTe device is analyzed.