Ultra-shallow junction formation for nano MOS devices using amorphous-si capping layer

Abstract

The present invention provides a new ultra-shallow junction formation method for nano-MOS technology applications by using conventional ion implantation and rapid thermal annealing techniques without requirement of low energy implant equipments to fabricate ultra-shallow junctions. Diffusion from implanted amorphous silicon (DIA) is performed by junction implant through an amorphous capping layer; the amorphous layer thus acts as a surface solid diffusion source during annealing. A thin oxide is deposited to serve as etching stop layer beneath the amorphous layer. This bilayer amorphous-oxide structure enables easy removal of the amorphous layer and provides good process control and device reliability. By using amorphous silicon layer as the diffusion source for junction formation, implant defects are reduced. Defect-free ultra-shallow junctions can be formed.