Si PRECURSORS FOR DEPOSITION OF SiN AT LOW TEMPERATURES

A plasma enhanced atomic layer deposition (PEALD) process for forming a silicon nitride thin film on a substrate in a reaction space comprising a plurality of deposition cycles, each deposition cycle comprising:

• alternately and sequentially contacting the substrate with a vapor phase silicon reactant and reactive species comprising nitrogen;
• wherein the vapor phase silicon reactant has the formula H2n+2−y−zSinXyAz, where X is I or Br, A is a halogen other than X and n=1, y=1 and z=0, and
• wherein a ratio of an etch rate of the silicon nitride thin film in 0.5% aqueous HF deposited on a vertical surface of a three-dimensional feature to an etch rate of the silicon nitride film in 0.5% aqueous HF deposited on a horizontal surface of the three-dimensional feature is less than 2.

The process of 13, wherein the nitrogen reactant gas comprises N2 and H2 gases.