Physical and Barrier Properties of PECVD Amorphous Silicon-Oxycarbide from Trimethylsilane and CO 2

Abstract

This work investigates the thermal stability and physical and barrier properties of amorphous silicon-carbide (α-SiC) and amorphous silicon-oxycarbide (α-SiCO) dielectric barriers deposited by plasma-enhanced chemical vapor deposition (PECVD) using trimethylsilane (3MS) precursor and He carrier gas. Films were deposited without and with various flow rates. The dielectric constant of the α-SiCO films decreased with increasing flow rate. Increasing flow rate also promotes better thermal stability, higher breakdown field, lower leakage current, and superior resistance to Cu diffusion through the films. The improved barrier property is attributed to the denser and less porous structure of the α-SiCO dielectric barrier upon addition. The α-SiCO barrier films deposited with the large (1200 sccm) flow rate exhibit the low k value of 3.7, thermal stability up to 550°C, room-temperature breakdown field of 8 MV/cm and leakage current densities of to A/cm2 at 3 MV/cm, and a superb Cu barrier property. © 2004 The Electrochemical Society. All rights reserved.