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Title: Formation of shallow junctions for VLSI by ion implantation and rapid thermal annealing

Thesis/Dissertation ·
OSTI ID:5210620

In this work, several techniques were studied to form shallow junctions in silicon by ion implantation. These include ion implantation through thin layers of silicon dioxide and ion implantation through a thick polycrystalline silicon layer. These techniques can be used to reduce the junction depth. Their main disadvantage is dopant loss in the surface layer. As an alternative, preamorphization of the Si substrate prior to boron implantation to reduce boron channeling was investigated. The disadvantage of preamorphization is the radiation damage introduced into the Si substrate using the implant. Preamorphization by silicon self-implantation has been studied before. The goal of this study was to test Ge as an alternative amorphizing agent. It was found that good-quality p{sup +}-n junctions can be formed by both boron and BF{sub 2} ion implantation into Ge-preamorphized Si provided that the preamorphization conditions are optimized. If the amorphous crystalline interface is sufficiently close to the surface, it is possible to completely remove the end-of-range damage. If these defects are not removed and are left in the depletion region, they can result in poor-quality, leaky junctions.

Research Organization:
North Carolina State Univ., Raleigh, NC (USA)
OSTI ID:
5210620
Resource Relation:
Other Information: Thesis (Ph. D.)
Country of Publication:
United States
Language:
English