METHODS OF DEFECT-ENGINEERING SHALLOW JUNCTIONS FORMED BY B-IMPLANTATION IN SI()

Control of dopant diffusion during high-temperature cycling is critica l in forming shallow electrical junctions in silicon as needed in inte grated-circuit manufacturing. However, junctions formed by implantatio n can be anomalously deep due to a transiency associated with ion-indu ced defects which greatly enhances dopant diffusion. The purpose of th is work was to investigate methods of defect engineering the implantat ion process to control or eliminate transient-enhanced diffusion (TED) . TED of boron has been attributed to excess interstitials introduced into the lattice during implantation, known as the plus-one model. Eff ects of pre-amorphization (i.e., amorphization prior to dopant implant ation using isoelectric ions) on TED of boron, and particularly, the r ole of the end-of-range (EOR) defects at the amorphous-crystalline int erface, are discussed. These EOR defects were varied by altering the i mplantation conditions during pre-amorphization. Also, other means of controlling the transiency are discussed, in particular, the use of hi gh-energy ions to introduce excess vacancies into the lattice where do pant diffusion occurs. These vacancies are shown to interact with the excess interstitials introduced during dopant implantation to suppress TED.