Lateral semiconductor power devices
Methods and systems for lateral power devices, and methods for operating them, in which charge balancing is implemented in a new way. In a first inventive teaching, the lateral conduction path is laterally flanked by regions of opposite conductivity type which are self-aligned to isolation trenches which define the surface geometry of the channel. In a second inventive teaching, which can be used separately or in synergistic combination with the first teaching, the drain regions are self-isolated. In a third inventive teaching, which can be used in synergistic combination with the first and/or second teachings, the source regions are also isolated from each other. In a fourth inventive teaching, the lateral conduction path is also overlain by an additional region of opposite conductivity type.
1. A lateral power semiconductor device, comprising:
a first-conductivity-type source region;
a second-conductivity-type body region, and a gate electrode which is capacitively coupled to a portion of the body region which is laterally adjacent to the source region;
a first-conductivity-type drain region;
a first-conductivity-type drift region, which is laterally interposed between the drain region and the body region in an electrical relation such that, when the gate electrode has a voltage which inverts part of the body region to form a channel therein, majority carriers can flow from the source region, through the channel, through the drift region, to the drain region;
wherein the source, body, drift, and drain regions are all located near a single surface of a second-conductivity-type semiconductor substrate, to permit predominantly lateral flow of carriers when a channel is present; and
second-conductivity-type charge balancing regions which laterally confine a portion of the drift region, and which are laterally flanked by insulating trenches;
wherein, when the gate is not inverting the body, and reverse bias is present between the source and drain regions, the drift region, and the charge balancing regions adjacent to the drift region, will be substantially depleted before breakdown occurs.
2. The lateral power semiconductor device of claim 1 , wherein the first conductivity type is n-type, and the second conductivity type is p-type.
3. The lateral power semiconductor device of claim 1 , wherein the semiconductor substrate is monolithic silicon.
4. The lateral power semiconductor device of claim 1 , wherein the semiconductor substrate is a semiconductor-on-insulator structure.
5. The lateral power semiconductor device of claim 1 , wherein the gate is insulated from the body region by a thin dielectric layer.
6. The lateral power semiconductor device of claim 1 , wherein the drift region overlaps the entire width of the gate electrode at an interface between the body region and the drift region.
7. A lateral power semiconductor device, comprising:
a first-conductivity-type source region;
a second-conductivity-type body region, and a gate electrode which is capacitively coupled to a portion of the body region;
a first-conductivity-type drain region;
a first-conductivity-type drift region, which is laterally interposed between the drain region and the body region in an electrical relation such that, when the gate electrode has a voltage which inverts part of the body region to form a channel therein, majority carriers can flow from the source region, through the channel, through the drift region, to the drain region;
wherein the source, body, drift, and drain regions are all located within a mass of second-conductivity-type semiconductor material;
second-conductivity-type charge balancing regions which laterally flank the drift region, and which are laterally flanked by insulating trenches; and
first-conductivity-type bottom regions below the trenches;
wherein, when reverse bias is present between the source and drain regions, the space charge of depleted portions of the second-conductivity-type charge balancing regions will at least partially balance the space charge of depleted portions of the drift region, and the space charge of depleted portions of the first-conductivity-type bottom regions will at least partially balance the space charge of depleted portions of the second-conductivity-type semiconductor mass.
8. The lateral power semiconductor device of claim 7 , wherein the first conductivity type is n-type, and the second conductivity type is p-type.
9. The lateral power semiconductor device of claim 7 , wherein the semiconductor substrate is monolithic silicon.
10. The lateral power semiconductor device of claim 7 , wherein the charge balancing regions are laterally flanked by insulating trenches.
11. The lateral power semiconductor device of claim 7 , wherein the semiconductor substrate is a semiconductor-on-insulator structure.
12. The lateral power semiconductor device of claim 7 , wherein the gate is insulated from the body region by a thin dielectric layer.
13. The lateral power semiconductor device of claim 7 , wherein the drift region overlaps a total width of the gate electrode at an interface between the body region and the drift region.
14. A lateral power semiconductor device, comprising:
a first-conductivity-type source region;
a second-conductivity-type body region, and a gate electrode which is capacitively coupled to a portion of the body region;
a first-conductivity-type drain region;
a first-conductivity-type drift region, which is laterally interposed between the drain region and the body region in an electrical relation such that, when the gate electrode has a voltage which inverts part of the body region to form a channel therein, majority carriers can flow from the source region, through the channel, laterally through the drift region, to the drain region;
wherein the source, body, drift, and drain regions are all located within a mass of second-conductivity-type semiconductor material;
second-conductivity-type charge balancing regions which laterally flank the drift region, and which are laterally flanked by insulating trenches; and
a second-conductivity-type upper region which overlies the drift region;
wherein, when reverse bias is present between the source and drain regions, the space charge of depleted portions of the second-conductivity-type charge balancing regions and of the upper region will at least partially balance the space charge of depleted portions of the drift region.
15. The lateral power semiconductor device of claim 14 , wherein the first conductivity type is n-type, and the second conductivity type is p-type.
16. The lateral power semiconductor device of claim 14 , wherein the semiconductor substrate is monolithic silicon.
17. The lateral power semiconductor device of claim 14 , wherein the charge balancing regions are laterally flanked by insulating trenches.
18. The lateral power semiconductor device of claim 14 , wherein the semiconductor substrate is a semiconductor-on-insulator structure.
19. The lateral power semiconductor device of claim 14 , wherein the gate is insulated from the body region by a thin dielectric layer.
20. The lateral power semiconductor device of claim 14 , wherein the drift region overlaps a total width of the gate electrode at an interface between the body region and the drift region.