Lifetime-killing defects in 4H-SiC epilayers and lifetime control by low-energy electron irradiation
Lifetime-killing defects in 4H-SiC epilayers and lifetime control by low-energy electron irradiation
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DOI：
10.1002/pssb.200844076
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发表时间：
2008-07-01
影响因子：
1.6
通讯作者：
Suda, Jun
中科院分区：
文献类型：
--
作者：
Kimoto, Tsunenobu;Danno, Katsunori;Suda, Jun
用微分微波光电导衰减测量方法研究了n型4 H-SiC外延层的载流子寿命。通过寿命与各种深能级之间的相关性研究，Z（1/2）和/或EH 6/7中心已被确定为有效的复合中心。当Z（1/2）（和EH 6/7）浓度高于10（13）cm（-3）时，载流子寿命与陷阱浓度成反比，并且寿命随激发强度（辐照光子密度）的增加而增加。或者，当Z（1/2）浓度小于10（13）cm（-3）时，其它复合过程限制寿命。在这种情况下，通过增加激发强度来降低载流子寿命。基于数值分析，提出了表面复合和基片内复合作为其它复合途径。通过低能电子辐照控制Z（1/2）（和EH 6/7）浓度，实现了寿命控制。(C)2008 WILEY-VCH Verlag GmbH & Co. KGaA，魏因海姆。
Carrier lifetimes in n-type 4H-SiC epilayers have been investigated by differential microwave photoconductance decay measurements. Through a correlation study between lifetime and various deep levels, the Z(1/2) and/or EH6/7 centers have been identified as effective recombination centers. When the Z(1/2) (and EH6/7) concentration is higher than 10(13) cm(-3), the inverse carrier lifetime is in proportion to the trap concentration, and the lifetime increases with increasing excitation intensity (density of irradiated photons). Alternatively, other recombination processes limit the lifetime when the Z(1/2) concentration is less than 10(13) cm(-3). In this case, the carrier life-time is decreased by increasing the excitation intensity. Surface recombination and recombination in the substrate have been suggested based on numerical analyses as the other recombination paths. By controlling the Z(1/2) (and EH6/7) concentration by low-energy electron irradiation, lifetime control has been achieved. (C) 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.