Patent ID: 8247022

Claim:
A method of forming a dual stack silicon nitride layer on a solar cell substrate, comprising: flowing a first process gas mixture into a processing chamber; generating plasma in the processing chamber; depositing a first silicon nitride-containing layer on at least one substrate in the processing chamber, wherein the first process gas mixture includes a total precursor gas mixture and a hydrogen gas (H 2 ) diluent, the flow rate of the hydrogen gas diluent being substantially equal to or greater than the flow rate of the total precursor gas mixture, and wherein the first silicon nitride-containing layer has a mass density of between about 2.6 and 2.8 g/cm 3 ; stopping the flow of the first process gas mixture; flowing a second process gas mixture into the processing chamber; and depositing a second silicon nitride-containing layer on the first silicon nitride-containing layer, wherein the second process gas mixture is selected from the group of gas mixtures consisting of silane (SiH 4 ) and nitrogen (N 2 ); silane, nitrogen and ammonia (NH 3 ); and silane and ammonia.