Patent ID: 8168462

Claim:
A method of forming a composite passivation layer on a solar cell substrate, comprising: providing a substrate having a p-type of doping atom on a back surface of the substrate and a n-type of doping atom on a front surface of the substrate forming a p-n junction region therebetween, wherein the substrate comprises a p-type substrate; plasma oxidizing the back surface of the substrate by a decoupled plasma oxidation process formed from a first gas mixture including an oxygen containing gas or a nitrogen containing gas at a process temperature less than 600 degrees Celsius to form an oxidation layer thereon; switching the first gas mixture to a second gas mixture including a silicon containing gas and a nitrogen containing gas; and forming a silicon nitride layer on the oxidation layer while maintaining the process temperature between about 300 degrees Celsius and about 500 degrees Celsius, wherein the oxidation layer and the silicon nitride layer are formed on the substrate in-situ in a single chamber.