Bonded-wafer superjunction semiconductor device
View Patent ↗A bonded-wafer semiconductor device includes a semiconductor substrate, a buried oxide layer disposed on a first main surface of the semiconductor substrate and a multi-layer device stack. The multi-layer device stack includes a first device layer of a first conductivity disposed on the buried oxide layer, a second device layer of a second conductivity disposed on the first device layer, a third device layer of the first conductivity disposed on the second device layer and a fourth device layer of the second conductivity disposed on the third device layer. A trench is formed in the multi-layer device stack. A mesa is defined by the trench. The mesa has first and second sidewalls. A first anode/cathode layer is disposed on a first sidewall of the multi-layer device stack, and a second anode/cathode layer is disposed on the second sidewall of the multi-layer device stack.
1. A bonded-wafer semiconductor device comprising:
a semiconductor substrate having first and second main surfaces opposite to each other;
a buried oxide layer disposed on at least a portion of the first main surface of the semiconductor substrate;
a multi-layer device stack having a first main surface and a second main surface, the multi-layer device stack including:
a first device layer of a first conductivity disposed on the buried oxide layer;
a second device layer of a second conductivity opposite to the first conductivity disposed on the first device layer;
a third device layer of the first conductivity disposed on the second device layer; and
a fourth device layer of the second conductivity disposed on the third device layer;
at least one trench formed in the first main surface of the multi-layer device stack, the at least one trench extending to a first depth position in the multi-layer device stack;
at least one mesa proximate the first main surface of the multi-layer device stack being defined by the at least one trench, the at least one mesa having a first sidewall and a second sidewall opposite the first sidewall;
a first anode/cathode layer disposed on a first sidewall of the multi-layer device stack; and
a second anode/cathode layer disposed on the second sidewall of the multi-layer device stack.
2. The bonded-wafer semiconductor device according to claim 1 , wherein the multi-layer device stack further includes:
a fifth device layer of the first conductivity disposed on the fourth device layer; and
a sixth device layer of the second conductivity disposed on the fifth device layer.
3. The bonded-wafer semiconductor device according to claim 2 , wherein the multi-layer device stack further includes:
a seventh device layer of the first conductivity disposed on the sixth device layer; and
an eighth device layer of the second conductivity disposed on the seventh device layer.
4. The bonded-wafer semiconductor device according to claim 1 , further comprising:
a heavily doped layer disposed on the second sidewall of the multi-layer device stack.
5. The bonded-wafer semiconductor device according to claim 1 , wherein a lateral Schottky diode is formed between the first and second anode/cathode layers through the multi-layer device stack.
6. The bonded-wafer semiconductor device according to claim 1 , wherein the first and second anode/cathode layers are formed of one or more of aluminum Al, aluminum silicon Al[% Si], copper Cu, gold Au, silver Ag, titanium Ti, tungsten W, nickel Ni, undoped polysilicon, doped polysilicon and combinations thereof.