The influence of nitrogen implantation on the properties of silicon-on-insulator buried oxide using separation by oxygen implantation was studied. Nitrogen ions were implanted into the buried oxide layer with a high-dose of 1016 cm-2.The experimental results showed that the positive charge density of the nitrogen-implanted buried oxide was obviously increased, compared with the control sampes without nitrogen implantation. It was also found that the post-implantation annealing caused an additional increase of the positive charge density in the nitrogen implanted samples. However,annealing time displayed a small effect on the positive charge density of the nitrogen implanted buried oxide, compared with the significant increase induced by nitrogen implantation. Moreover, the capacitance-voltage results showed that the positive charge density of the unannealed sample with nitrogen implanted is approximately equal to that of the sample annealed at 1100 ℃ for 2. 5 h in N2 ambient, despite an additional increase brought with annealing, and the buried oxide of the sample after 0.5 h annealing has a maximum value of positive charge density. According to the simulating results,the nitrogen implantation resulted in a heavy damage to the buried oxide, a lot of silicon and oxygen vacancies were introduced in the buried oxide during implantation. However, the Fourier transform infrared spectroscopy of the samples indicates that implantation induced defects can be basically eliminated after an annealing at 1100 ℃ for 0. 5 h. The increase of the positive charge density of the nitrogen implanted buried oxide is ascribed to the accumulation of implanted nitrogen near the interface of buried oxide and silicon, which caused the break of weak Si - Si bonds and the production of positive silicon ions in the silicon-rich region of the buried oxide near the interface, and this conclusion is supported by the results of secondary ion mass spectrometry.%为研究注氮改性对注氧隔离硅材料中埋氧层性质的影响,向其埋氧层内注入了1016 cm-2的高剂量氮.实验结果表明,与未注氮的埋氧层相比,所有注氮的埋氧层中的正电荷密度显著增加.实验还发现,注氮后的退火可使埋氧层内的正电荷密度进一步上升.但与注氮导致的埋氧层内正电荷密度的显著上升相比,退火时间对注氮的埋氧层内正电荷密度的影响不大.电容-电压测量结果显示,在埋氧层内部,注氮后未退火的样品与在1100℃的氮气气氛下退火2.5 h的样品相比,二者具有近似相同的等效正电荷面密度.然而,经0.5 h退火的样品却对应最高的等效电荷面密度.为探讨注氮埋氧层内正电荷产生的机理,对注氮在埋氧层中导致的注入损伤进行了模拟.模拟结果表明,氮离子注入在埋氧层内引入了大量的空位缺陷.对比注氮与退火前后的傅里叶变换红外光谱发现,注入损伤在经0.5 h的高温退火后即可基本消除.实验还对退火前后的注氮样品进行了二次离子质谱分析.分析认为,注入的氮在埋氧层与硅界面附近积累,导致近界面富硅区的硅-硅弱键断裂是注氮埋氧层内正电荷密度增加的主要原因.
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