Patent ID: 8802970

Claim:
A method of making a photovoltaic cell comprising: a. providing a silicon wafer having a first side and a second side, b. applying a phosphorus source to the first side of the silicon wafer, c. firing the wafer to form a phosphorus glass layer on the first side of the silicon wafer, d. removing at least a portion of the phosphorus glass layer from the first side of the silicon wafer, e. polishing the second side of the silicon wafer, f. applying a passivating layer to the first and second sides of the wafer, g. applying to the first side a silver paste comprising, prior to firing, i. silver, ii. a glass component, and iii. a vehicle, h. applying to the second side an aluminum paste comprising, prior to firing, i. aluminum, ii. a glass component, and iii. a vehicle, wherein (g) and (h) can be performed in any order, and i. firing the wafer for a time and temperature sufficient to adhere the silver to the front side and the aluminum to the back side, thereby forming front and back contacts.