以超高真空化學氣相沉積系統成長矽硼層在超大型積體電路之應用

Abstract

本論文利用超高真空化學氣相沉積系統成長矽硼層，此一矽硼層具有很高 的硼原子濃度，而矽硼層中及矽硼層經過退火後均有SiB6析出物;實驗結 果顯示此一矽硼層可作為硼原子擴散源，而以矽硼層作為擴散源之複晶矽 接觸二極體其淺接面深度遠比BF2植入複晶矽為擴散源更淺，且其電性特 性亦較為優越。此外，本論文亦研究鈦 /矽硼層之反應特性，由實驗結果 顯示此一系統之矽化物/矽介面比傳統的複晶矽化鈦平坦且一致，而其接 觸二極體亦具有較優越且穩定的電性特性。 This dissertation presents a new material,Si-B layer,as a diffusion source for doping p+ poly-Si. The Si-B layer was grown in an UHV/CVD systems. The results indicated that Si-B layer can be regarded as an infinite diffusion source of boron atoms. In the poly-Si/Si system, the junction depths of Si-B layer source were much shallower and less sensitive to thermal budget than that of BF2 source. It was attributed to the smaller surface concentration and diffusivity of boron in the silicon for the Si-B layer source. The electrical characteristics and uniformity of Si-B-source diodes are much better than that of BF2 source diodes. The interaction of Ti with Si-B layer in an N2 ambient have been investigated. For one step sintering,a TiN/TiSi2/Ti-Si-B trilayer was formed after sintering. For two two step sintering a TiSi2/Ti-Si-B bilayer was formed after sintering. As comparing with Ti/poly- Si system,the reaction rate of Ti/Si-B layer is suppressed and the phase transform is reduced. The surface morphology and thermal stability of TiSi2 /Ti-Si-B is better than that of conventional Ti-polycide. A electrical properties for TiSi2/Ti- Si-B contacted diodes was attributed the smoother silicide/Si interface and the better stability of silicide.