Reduction of Leakage Current for Shallow n + / p Junction Fabricated Using C49 TiSi2 as a Diffusion Source

Abstract

This paper describes a method for low reverse leakage current in titanium‐silicided shallow junctions featuring mediated ion implantation of Ti silicide (MITS). After deposition of Ti film, a first heat treatment was performed to formed C49 Ti silicide. MITS arsenic ions were implanted and a second heat‐treatment was carried out at 850°C to form C54 Ti silicide. In spite of no drive‐in process following the second annealing, the implanted As diffused well into Si substrate and the reverse leakage current of the junctions was greatly reduced from 200 to . The reason for fast diffusivity is supposed to be the generation of high tensile stress induced by As implantation, while normal C49 Ti silicide film constantly shows compressive stress. This technique satisfies low sheet resistance (<5 Ω/□) and low leakage current of Ti silicide shallow junctions simultaneously. Therefore, we can conclude that C49 can be used a diffusion source without causing further short‐channel effects and punchthrough in subquarter micrometer n‐MOSFETs. © 1999 The Electrochemical Society. All rights reserved.