SiGe缓冲层对β-SiC(n)/c-Si(p)异质结特性的影响

Effect of SiGe Buffer Layer on Characteristics of β-SiC(n)/c-Si(p) Heterojunctions

SiC/Si的界面特性严重影响着SiC/Si异质结的电学特性及光学特性.在β-SiC(n)/c-Si(p)异质结中引入Si Ge缓冲层,构造了Al/β-SiC(n)/Si Ge/c-Si(p)/Al典型的三明治异质结结构.对带有和不带Si Ge缓冲层的β-SiC(n)/c-Si(p)异质结的界面SEM图像,正反向I-V特性曲线及QE作了对比研究,理论和实验均表明,Si Ge缓冲层的引入可以有效地改善β-SiC(n)/c-Si(p)异质结的界面特性,减少界面缺陷,从而提高异质结的反向击穿电压及整流比,展宽异质结光谱响应范围,提高量子效率QE,且使QE的峰值点发生明显红移.

The property of SiC/Si interface has a significant effect on electric and optical characteristics of SiC/Si heterojunetions. In this paper,SiGe buffer layer is introduced into β-SiC（n）/c-Si（p） heterojunctions and typical Al/β-SiC（n）/SiGe/c-Si（p）/Al sandwich structure is fabricated. To β-SiC（n）/c-Si（p） heterojunctions with and without SiGe buffer layer, SEM images of interface, forward and reverse bias I-V characteristics and QE of spectrum response are comparatively studied. Theory and experimental results all indicate that introduction of SiGe buffer layer can efficiently improve the interfaee property, decrease defaults density of β-SiC（n）/e-Si（p） heterojunctions,so that reverse breakdown voltage and RR of heterojunctions are increased, range of spectrum response is widen,QE of heterojunctions is increased and the peak point of QE makes obvious red-shift.