n型硅脉冲激光掺铟的物理过程与缺陷特性研究

A STUDY ON THE PHYSICAL PROCESS OF INDIUM IMPLANTATION BY PULSE LASER AND THE DEFECT PROPERTIES IN n TYPE SILICON

用Nd-YAG脉冲激光对n型硅掺铟,形成外p^+n结。利用二次离子质谱仪(SIMS)、卢瑟福背散射(RBS)等方法,研究了硅内铟的分布,并分析了用20ns脉冲激光硅掺铟的物理过程,发现当激光能量密度足够大时,在硅表面层存在硅-铟混合熔体和液态硅两部分。当激光能量密度较小时,硅表面层仅有液态硅层、用I-V,C-V和深能级瞬态谱(DLTS)等方法研究了p^+n结的电学性质,发现在p^+n结的n区存在两个缺陷。一个能通过快速热退火,在600℃,60s条件下消失,研究表明可能为空位与杂质的复合体。另一个通过快速热退火不能消失,可能与位错有关。

In this paper, implantation of indium atoms into silicon forming pn juction by Nd-YAG pulse laser irradiation was reported. The indium depth profile in silicon has been determined by secondary ion mass spectrscopy (SIMS) and Rutherford backscatting spectroscopy (RBS). The results can be ascribed to a qualitative model for the physical process of implantation indium in 20ns pulse laser irradiation. Namely, if the laser energy density exceeds a certain threshold, there exist two parts at the surface layer of silicon, silicon-indium molten mixture and liquid state silicon. But only the liquid state silicon layer exists at the surface if the laser energy density does not reach that threshold. The pn juction has good properties revealed by means of I-V and C-V measurements. The results of deep level transient spectroscopy (DLTS) show that there are two kinds of defects in pn juction. One kind of the defects (E1) disappears at 600癈, 60s in rapid thermal annealing (RTA) and the study shows that the defect E1 may be the impurity-vacancy complex. The other defects E2 would not disappear in RTA and may be related to the dislocations.