Patent ID: 7446018

Claim:
A method of manufacturing a bonded-wafer semiconductor device comprising: providing a first semiconductor substrate having first and second main surfaces opposite to each other; depositing an oxide layer on the first main surface of the first semiconductor substrate; providing a second semiconductor substrate having first and second main surfaces opposite to each other, the second semiconductor substrate being of a first conductivity; doping the first main surface of the second semiconductor substrate with a first dopant of a second conductivity opposite to the first conductivity; placing the doped first main surface of the second semiconductor substrate onto the oxide layer on the first main surface of the first semiconductor substrate; annealing/bonding the second semiconductor substrate to the oxide layer thereby diffusing the first dopant into the second semiconductor substrate to create a first device layer of the second conductivity and a second device layer of the first conductivity; doping the second main surface of the second semiconductor substrate with a second dopant of the second conductivity; and diffusing the second dopant into the second semiconductor substrate to form a third device layer of the second conductivity.