Patent ID: 7939455

Claim:
A method of depositing a strained SiN film on a substrate in a process chamber, comprising: a) exposing the substrate to a first gas pulse comprising a silicon precursor; b) exposing the substrate to a gas pulse comprising a first nitrogen precursor, or a gas pulse comprising the first nitrogen precursor and a second nitrogen precursor in a first ratio, configured to react with the silicon precursor of the first gas pulse with a first reactivity characteristic to form a first SiN layer having a first density; c) exposing the substrate to a second gas pulse comprising the silicon precursor; and d) exposing the substrate to a gas pulse comprising the second nitrogen precursor, or a gas pulse comprising the first and second nitrogen precursors in a second ratio different from the first ratio, configured to react with the silicon precursor of the second gas pulse with a second reactivity characteristic different than said first reactivity characteristic to form, on the first SiN layer, a second SiN layer having a second density different from the first density, such that a property of the SiN film formed on the substrate changes to provide the strained SiN film, and e) repeating the steps a)-d) a predetermined number of times, wherein a separate gas pulse comprising the silicon precursor is exposed to the substrate for each gas pulse comprising the first nitrogen precursor or the first and second nitrogen precursors in the first ratio, and for each gas pulse comprising the second nitrogen precursor or the first and second nitrogen precursors in the second ratio.