Bidirectional bipolar transistors with two-surface cellular geometries
A two-surface bidirectional power bipolar transistor is constructed with a two-surface cellular layout. Each emitter/collector region (e.g. doped n-type) is a local center of the repeated pattern, and is surrounded by a trench with an insulated field plate, which is tied to the potential of the emitter/collector region. The outer (other) side of this field plate trench is preferably surrounded by a base connection region (e.g. p-type), which provides an ohmic connection to the substrate. The substrate itself serves as the transistor's base.
1. A bidirectional power bipolar transistor device, comprising:
a p-type semiconductor die having, on each of the two surfaces thereof, a plurality of separate n-type emitter/collector regions, each of which is surrounded by a first insulating trench;
a plurality of p-type base connection regions, each surrounding one of the first insulating trenches;
a p-type base connection contact region, surrounding multiple ones of the base connection regions, and set back from the insulating trenches;
wherein the density of the emitter/collector regions on either of the surfaces is the same as the density of the emitter/collector regions on the other of the surfaces.
2. The device of claim 1 , wherein the semiconductor die is silicon.
3. A bidirectional power bipolar transistor device, comprising:
a p-type semiconductor die having, on each of the two surfaces thereof, a plurality of separate n-type emitter/collector regions, each of which is surrounded by a first insulating trench;
a plurality of p-type base connection regions, each surrounding one of the first insulating trenches;
a p-type base connection contact region, surrounding multiple ones of the base connection regions, and set back from the insulating trenches;
wherein the density of the emitter/collector regions on either of the surfaces is the same as the density of the emitter/collector regions on the other of the surfaces;
wherein the emitter/collector regions on the two surfaces are aligned with each other.
4. The device of claim 3 , wherein the semiconductor die is silicon.
5. A bidirectional power bipolar transistor device, comprising:
a p-type semiconductor die having, on each of the two surfaces thereof, a plurality of separate n-type emitter/collector regions, each of which is surrounded by a first insulating trench;
a plurality of p-type base connection regions, each surrounding one of the first insulating trenches;
a p-type base connection contact region, surrounding multiple ones of the base connection regions, and set back from the insulating trenches;
a metallization connected to said emitter/collector regions and to said insulating trenches;
wherein the density of the emitter/collector regions on either of the surfaces is the same as the density of the emitter/collector regions on the other of the surfaces.
6. The device of claim 5 , wherein the semiconductor die is silicon.