非掺杂区对GaAs隧道结的优化  

Optimization of the Undoped Region on the GaAs Tunnel Junction

作　　者：张曦[1] 韩颖[1] 杨建业[1] 师巨亮[1] 夏英杰[1] 

机构地区：[1]中国电子科技集团公司第十三研究所,石家庄050051

出　　处：《微纳电子技术》2016年第6期369-373,共5页Micronanoelectronic Technology

摘　　要：有效提高隧道结的峰值隧道电流密度(J_p)是提高多结太阳电池(MJSC)聚光倍数和光电转换效率的关键。根据有限表面源扩散原理求解Fick扩散方程得到了隧道结界面处杂质扩散浓度分布,发现隧道结界面处的杂质扩散会增加空间电荷区宽度,导致隧道结的J_p降低。通过在隧道结中间加入非掺杂区(Ⅰ区)的方法对隧道结结构进行优化,分析得出厚度合适的Ⅰ区可以减小界面处杂质扩散带来的不利影响。基于该分析设计了一系列GaAs隧道结结构,采用分子束外延(MBE)技术获得了外延样品,结果表明在生长温度和掺杂浓度不变的情况下,隧道结中加入合适厚度的Ⅰ区可以提高J_p。The effective enhancement of the peak tunneling current density（J_p） of the tunnel junction is the key to improve the concentrated ratio and photoelectric conversion efficiency of the multi-junction solar cell（MJSC）.According to the principle of the finite surface source diffusion,the impurity diffusion concentration distribution at the tunnel junction interface was obtained by solving the Fick diffusion equation.It is found that the impurity diffusion at the tunnel junction interface can increase the width of the space charge region,thus J_p of the tunnel junction decreases.The tunnel junction structure was optimized by adding the undoped region（Ⅰ region） in the middle of the tunnel junction.The analysis result shows that the negative influence of the interface impurity diffusion is reduced by selecting the appropriate thickness of Ⅰ region.A series of GaAs tunnel junction structures were designed based on the analysis.The epitaxy samples were grown by the molecular beam epitaxy（MBE）.The result shows that J_p can be improved by adding Ⅰ region with appropriate thickness in the tunnel junction under the constant grow temperature and doping concentration.

关 键 词：隧道结 峰值隧道电流密度 非掺杂区 杂质扩散 分子束外延(MBE) 

分 类 号：TN304.054[电子电信—物理电子学] TN304.23