Effects of TiCl4-Based PECVD-Ti/CVD-TiN Barrier Layers on the BF2-Doped Si for Contact Plug Technology

Abstract

We have performed the investigation of Ti/TiN barrier layers deposited by PECVD of Ti and CVD of TiN using TiCl 4 as a reactant on a heavily boron doped Si substrate. High contact resistance arose from both the boron out-diffusion, and high chlorine content in the Ti film with respect to the relatively high, and low process temperatures of PECVD-Ti deposition, respectively. In the optimized PECVD-Ti process condition with the satisfied boron dose in the Si substrate, comparable yields can be achieved with that using the 110nm deep trench Dynamic Random Access Memory (DRAM) technology with PVD-Ti method. Furthermore, using PECVD-Ti/CVD-TiN method for the contact metallization, it can obtain a uniform thickness of liner in the hole-type contact with aspect ratio to 6.