以快速退火法研製矽化鉑接觸之淺接面

Abstract

本論文主旨在研究以離子佈植穿透矽化物 (ITS)､離子佈植穿透金屬 (ITM)､ 及以快速退火 (RTA)方式製備之矽化鉑接觸的 p﹢n 淺接面。實 驗結果顯示此快速退火方式確實可有效地抑制硼離子的擴散，並且具備強 大的缺陷復原能力。研究結果證實用ITM╱ITS 技術及750℃╱40s 的快速 退火可以獲得高性能之矽化鉑接觸的p﹢n二極體﹐其接面深度70奈米及逆 向漏電流密度2 奈安╱平方公分，而且以ITM 方式製成的接面特性是優於 以ITS 方式製成者。此外，本研究並以二次佈植(F﹢+ BF2﹢)法製備之淺 接面探討氟離子對接面特性的影響；我們發現前置佈植之氟離子確實可形 成非常淺的接面並改善PtSi╱p﹢n的高溫穩定性。這項結果顯然是由於氟 佈植造成矽表面的非晶化，使後續的BF2﹢ 佈植中，硼離子的穿透效應減 少以及將更多的氟離子摻入矽化鉑╱矽的結構中所致。另一方面，本研究 也對於完全快速溫度製程，即以快速矽化及快速退火所製備的淺接面，做 初步的探討。 This thesis studies the formation of PtSi contacted p﹢n shallow junctions by ITS(implant-through-silicide)╱ITM( implant- through-metal) BF2﹢ implantation and rapid thermal annealing ( RTA)technique. The experimental result shows that RTA annealing results in less boron diffusion and powerful implantation damage removing ability. High performance PtSi/p﹢ n diodes with a junc- tion depth of about 70nm and leakage current density of 2nA/ｃ㎡ can be obtained with ITS╱ITM BF2﹢ implantation followed by RTA 750℃/40s annealing. It is found that the junction characteris- tics of the diodes made by ITM scheme are generally superior to that of the diodes made by ITS scheme. The dual implantation ( B﹢ + BF2﹢) scheme was also employed to investigate the effect of F﹢ pre-implantation. It turns out that the F﹢ pre-implan- tion leads to an ultrashallow junction with improved high-tem- perature stability. This is apparently due to pre-amorphization of Si surface, which reduces the channeling effect of subsequent BF2 ﹢ implantation, and more effective fluorine ions incorpation into the PtSi╱Si structure. The full rapid thermal processing( RTP), which consists of PtSi silicidation by RTP followed by RTA annealing, was also brief investigated.