中子辐照SiC及其退火行为的光致发光特性研究
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摘要
利用荧光光谱对剂量为1.72×10~(19)n/cm~2的中子辐照掺氮6H-Si C晶体的发光特性进行了研究。结果表明:中子辐照在晶体中产生了大量缺陷,导致晶格结构发生严重损伤,使N有关的施主-受主对遭到破坏,引起对应的560nm发光峰消失;同时辐照缺陷引起的晶格应力使417nm和438nm附近发光峰发生轻微的蓝移现象。对辐照样品进行800℃和1600℃的等时退火后,发现低温800℃退火并未引起辐照损伤的明显恢复;经1600℃退火处理后,560nm发光峰明显升高,而417nm和438nm发光峰显著降低几乎趋于零,说明高温退火导致晶格损伤完全恢复,甚至使晶体中的固有缺陷也得到一定程度的恢复。
The optical properties revealing annealing behavior of N-doped 6H-SiC neutron irradiated at a fluence of 1. 72 × 10~(19)n/cm~2 have been studied by Photoluminescence( PL) Spectroscopy. The results showed that 560 nm peak with related to donor-accepter pair involving nitrogen was disappeared after neutron irradiation,indicating the serious damage of single crystal structure induced by large amount of optical defects.Simultaneously,the slightly blue shift near 417 nm and 438 nm peaks position attributed to crystal lattice stress induced by irradiated defects. By isochronal annealing at 800℃ and 1600℃ for 30 min,the irradiated lattice damage had not been obviously recovered under the lower temperature. However,after annealing at 1600℃,the intensity of 560 nm peak was recovered considerably and higher than the value before irradiation,meanwhile,417 nm and 438 nm peaks were reduced significantly with their intensity reaching almost to zero. This indicates the elimination or reduction of irradiation induced lattice damage and the possible recovery of some inherent defects in original crystal.
The optical properties revealing annealing behavior of N-doped 6H-SiC neutron irradiated at a fluence of 1. 72 × 10~(19)n/cm~2 have been studied by Photoluminescence( PL) Spectroscopy. The results showed that 560 nm peak with related to donor-accepter pair involving nitrogen was disappeared after neutron irradiation,indicating the serious damage of single crystal structure induced by large amount of optical defects.Simultaneously,the slightly blue shift near 417 nm and 438 nm peaks position attributed to crystal lattice stress induced by irradiated defects. By isochronal annealing at 800℃ and 1600℃ for 30 min,the irradiated lattice damage had not been obviously recovered under the lower temperature. However,after annealing at 1600℃,the intensity of 560 nm peak was recovered considerably and higher than the value before irradiation,meanwhile,417 nm and 438 nm peaks were reduced significantly with their intensity reaching almost to zero. This indicates the elimination or reduction of irradiation induced lattice damage and the possible recovery of some inherent defects in original crystal.
引文
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[2]Fenici P,Frias Rebelo A J,Jones R H,et al.Current status of Si C/Si C composites R&D[J].J.Nucl.Mater.,1998,258.
[3]王玉霞,何海平,汤红高.宽带隙半导体材料Si C研究进展及其应用[J].硅酸盐学报,2002(3).
[4]Z.C.Feng,S.J.Chua,K.Tone and J.H.Zhao.Recrystallization of carbon–aluminum ion coimplanted epitaxial silicon carbide—evidenced by room temperature optical measurements[J].Applied Physics Letters,1999,75(4).
[5]张洪华,张崇宏,李炳生等.碳化硅氦离子高温注入引入的缺陷及其退火行为的光谱研究[J].物理学报,2009(5).
[6]P.J.Wellmann,S.Bushevoy and R.Weingartner.Evaluation of n-type doping of 4H-Si C and n-/ptype doping of 6H-Si C using absorption measurements[J],Mater.Sci.Engin.B,2001,80(1-3).
[7]Z.Y.Zhang,X.L.Wu,S.J.Xiong,et al.On the origin of the 417 and 437 nm double-peak emission in porous Si with crystallite smaller than 3.0 nm[J].Physics Letters A,2003,313(5).
[8]M.Yoganathan,W.J.Choyke and R.P.Devaty.Free to bound transition-related electroluminescence in 3C and6H-Si C p+–n junctions at room temperature[J].Journal of Applied Physics,1996,80(3).
[9]Y.Kawai,T.Maeda,Y.Nakamura,et al.6H-Si C homoepitaxial growth and optical property of boron-and Nitrogen-doped donor-acceptor pair(DAP)emission of1o-off substrate by closed-space sublimation method[J].Materials Science Forum,2006,527-529.
[10]S.Fung,X.D.Chen,C.D.Beling,et al.Photoluminescence study of beryllium implantation induced intrinsic defects in 6H-silicon carbide[J].Physica B:Condensed Matter,2001,308.
[11]贾仁需,张义门,张玉明等,4H-Si C同质外延的绿带发光与缺陷的关系[J].物理学报,2008(7).
[12]R.Héliou,J.L.Brebner,S.Roorda.Optical and structural properties of 6H-Si C implanted with silicon as a function of implantation dose and temperature[J].Nucl.Instrum.MethodsPhys.Res.B,2001,175-177.
[13]N.T.Son,W.M.Chen,J.L.Lindstr?m1,et al,Carbonvacancy related defects in 4H-and 6H-Si C[J].Materials Science and Engineering B,1999,61-62.