Surface passivation in n-type silicon and its application in silicon drift detector  

作　　者：Yiqing Wu Ke Tao Shuai Jiang Rui Jia Ye Huang 吴怡清;陶科;姜帅;贾锐;黄也(School of Physical and Electronic Science,Changsha University of Science and Technology,Changsha 410114,China;Institute of Microelectronics,Chinese Academy of Sciences,Beijing 100029,China)

机构地区：[1]School of Physical and Electronic Science,Changsha University of Science and Technology,Changsha 410114,China [2]Institute of Microelectronics,Chinese Academy of Sciences,Beijing 100029,China

出　　处：《Chinese Physics B》2020年第3期406-411,共6页中国物理B（英文版）

基　　金：Project supported by the National Natural Science Foundation of China(Grant Nos.51602340,51702355,and 61674167);the Natural Science Foundation of Beijing Municipality of China(Grant No.4192064);the National Key Research Program of China(Grant Nos.2018YFB1500500 and 2018YFB1500200);the JKW Project of China(Grant No.31512060106)。

摘　　要：Based on the surface passivation of n-type silicon in a silicon drift detector(SDD), we propose a new passivation structure of SiO2/Al2O3/SiO2 passivation stacks. Since the SiO2 formed by the nitric-acid-oxidation-of-silicon(NAOS)method has good compactness and simple process, the first layer film is formed by the NAOS method. The Al2O3 film is also introduced into the passivation stacks owing to exceptional advantages such as good interface characteristic and simple process. In addition, for requirements of thickness and deposition temperature, the third layer of the SiO2 film is deposited by plasma enhanced chemical vapor deposition(PECVD). The deposition of the SiO2 film by PECVD is a low-temperature process and has a high deposition rate, which causes little damage to the device and makes the SiO2 film very suitable for serving as the third passivation layer. The passivation approach of stacks can saturate dangling bonds at the interface between stacks and the silicon substrate, and provide positive charge to optimize the field passivation of the n-type substrate.The passivation method ultimately achieves a good combination of chemical and field passivations. Experimental results show that with the passivation structure of SiO2/Al2O3/SiO2, the final minority carrier lifetime reaches 5223 μs at injection of 5×10^(15) cm^(-3). When it is applied to the passivation of SDD, the leakage current is reduced to the order of nA.Based on the surface passivation of n-type silicon in a silicon drift detector（SDD）, we propose a new passivation structure of SiO2/Al2O3/SiO2 passivation stacks. Since the SiO2 formed by the nitric-acid-oxidation-of-silicon（NAOS）method has good compactness and simple process, the first layer film is formed by the NAOS method. The Al2O3 film is also introduced into the passivation stacks owing to exceptional advantages such as good interface characteristic and simple process. In addition, for requirements of thickness and deposition temperature, the third layer of the SiO2 film is deposited by plasma enhanced chemical vapor deposition（PECVD）. The deposition of the SiO2 film by PECVD is a low-temperature process and has a high deposition rate, which causes little damage to the device and makes the SiO2 film very suitable for serving as the third passivation layer. The passivation approach of stacks can saturate dangling bonds at the interface between stacks and the silicon substrate, and provide positive charge to optimize the field passivation of the n-type substrate.The passivation method ultimately achieves a good combination of chemical and field passivations. Experimental results show that with the passivation structure of SiO2/Al2O3/SiO2, the final minority carrier lifetime reaches 5223 μs at injection of 5×1015 cm-3. When it is applied to the passivation of SDD, the leakage current is reduced to the order of nA.

关 键 词：SiO2/Al2O3/SiO2 STACKS CHEMICAL PASSIVATION field PASSIVATION silicon DRIFT DETECTOR 

分 类 号：TN305[电子电信—物理电子学]