Characterization of lateral dopant diffusion in silicides

Abstract

The lateral diffusion of dopants in silicides has been studied using a new and sensitive Schottky barrier test structure that relies on changes in the I-V characteristics of silicidelsilicon interfaces due to dopant diffusion from a doped silicide into silicon. The test structure has been used to determine the diffusivity of As and B in WSiz and Ti&. The diffusion process is modeled as a 1-D diffusion from a constant concentration dopant source. The diffusivity of B and As in WSiz is found to be 1.0 x exp [ = # I cmz/sec and 2.6 exp [*] cm2/sec respectively. The diffusivity of As in TiSiz is 4.8 exp ( 9 1 cm2/sec. No measurable lateral diffusion of B in has been obsetved. The process flow of the test structure makes the device readily adaptable to other deposited or reacted silicides.