Novel plasma enhanced chemical vapor deposition of highly conformal SiN films and their barrier properties

Abstract

A novel plasma-enhanced chemical vapor deposition technique was used to fabricate highly conformal silicon nitride (SiN) films and study their barrier properties. Trisilylamine was used as the main precursor and was introduced into the reaction chamber in 0.3-s pulses while the plasma was excited. The deposited SiN film exhibited good conformality (91%) and an aspect ratio of similar to 4.2 (a width of 70 nm and a depth of 300 nm). The film growth rate was 2.0 angstrom/cycle. The k-value and leakage current were 7.1-6.66 and lower than 1.0 x 10(-8) A/cm(2), respectively, at a 1 MV charge (8.5 x 10(-10)-3.5 x 10(-8) A/cm(2)) in the temperature range of 200-400 degrees C. The wet etch rates of the SiN deposition at 200 and 400 degrees C were 32.1 and 11.1 nm/min, respectively. The wet etch rate of the films was evaluated in a dilute hydrogen fluoride (HF) solution (H2O: HF = 100: 1). The 5.0-nm thick SiN films deposited at 200 and 400 degrees C exhibited excellent abilities to prevent moisture from entering. By modifying the supply method of the Si precursor, the step coverage improved to the plasma enhanced atomic layer deposition level and the moisture barrier property was maintained even at thicknesses of less than 10 nm. Published by the AVS.