矽化鎳接觸之P+N淺接面特性研究

Abstract

為了減少短通道的效應,降低源/汲極上的接觸電阻,同時為了增進元件與 電路的表現,金屬矽化淺接面應用在超大型積體電路上非常重要.在本論文 中,吾人採用鎳金屬作為金屬矽化物,因矽化鎳具有寬的製程溫度,在源/汲 極與閘極間無橫向生長的特性,以及低的矽消耗等等優點.此外,本文利用 不同的技術來形成矽化淺接面.首先運用鎳金屬薄膜來當做離子佈植障礙 層,接著利用矽化鎳當做佈植障礙層,其次是以非晶矽薄膜做為佈植障礙 層,由於非晶矽薄膜對佈植的硼離子具有很好的阻擋效果,因而形成較淺的 矽化淺接面.最後吾人提出一種新式的結構來形成金屬矽化淺接面.此結構 是在元件的主動區先沉積一層非晶矽,接著鍍上鎳金屬薄膜,利用鎳金屬與 非晶矽的雙層結構做為離子佈植障礙層.本文中並探討不同技術形成金屬 矽化物的高溫熱穩定性,以及接面漏電流的特性. To minimize the short channel effect and reduce the contact resistance of the source/drain and electroded as well as interconnections, metal silicides have been used to apply in very-large-scale-integration(VLSI) for improving submicrometer devices and circuit performance. In thesis, nickel silicide would be a proper material because of the wide temperature process window, good resistance to lateral growth between the gate and the source/drain, and less silicon consumtion during silicidation. Moreover, various techniques have been used to form silicided shallow junctions. The first method to make silicided shallow junctions is to deposit a layer of metal and then implant dopants through the metal layer(ITM). The following technique is using the nickel silicide as implantation barrier. To achieve the shallow junctions and low reverse leakage current, it is severe preventing boron peneration during silicidation. A method which is proposed is to deposit a layer of amorphous silicon(a-Si) and then implant dopants through the a-Si layer. The boron channeling is effectively elimenated by the ITA scheme. Another novel structure which is proposed to deposit a metal layer on the amorphous silicon layer and then implant dopants through the metal/Si(ITMA). In this thesis, the high temperature thermal stability of the nickel silicide and the electrical characteristics of p+n junctions have also been investigated.