Lateral transistors and methods with low-voltage-drop shunt to body diode
AssigneeMaxPower Semiconductor, Inc.
InventorsMohamed N. Darwish, Jun Zeng, Richard A. Blanchard
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Abstract
Methods and systems for power semiconductor devices integrating multiple quasi-vertical transistors on a single chip. Multiple power transistors (or active regions) are paralleled, but one transistor has a lower threshold voltage. This reduces the voltage drop when the transistor is forward-biased. In an alternative embodiment, the power device with lower threshold voltage is simply connected as a depletion diode, to thereby shunt the body diodes of the active transistors, without affecting turn-on and ON-state behavior.
Claims19
A power semiconductor device, comprising:
- a first and second group of laterally-gated transistors integrated on a single semiconductor die, each said laterally-gated transistor having a first-conductivity-type source region, and a gate electrode which is capacitively coupled to a body region to selectably form a lateral channel therein, and a vertically-extended conduction region connecting a drain region to a drain extension region which is adjacent to said lateral channel;
- wherein the threshold voltages of said first group of laterally-gated transistors are lower than the threshold voltages of said second group of laterally-gated transistors;
- wherein the vertically-extended conduction region of at least each said second laterally-gated transistor is provided by fixed electrostatic charges in the walls of a trenched field plate, which invert a portion of said body region;
- and
- wherein the widths of said first group of laterally-gated transistors are narrower than the widths of said second group of laterally-gated transistors.
A power semiconductor device, comprising:
- a first and a second laterally-gated transistor both having a portion of a first-conductivity-type source region, a gate electrode which is capacitively coupled to a body region to selectably form a lateral channel therein, a first-conductivity-type drain extension region connecting said lateral channel to a common drain electrode, a vertically-extended source extension region connecting said source region to a common source electrode on the backside of the device, and a shorting strap connecting said source region to said vertically-extended source extension region;
- wherein both said gate electrodes are electrically separate portions of a single thin film layer;
- wherein the threshold voltage of said first laterally-gated transistor is less than the threshold voltage of said second laterally-gated transistor;
- and
- wherein said first laterally-gated transistor has a width which is smaller than a width of said second laterally-gated transistor.
A power semiconductor device, comprising:
- a first and a second laterally-gated transistor both having a portion of a first-conductivity-type source region, a gate electrode which is capacitively coupled to a body region to selectably form a lateral channel therein, a first-conductivity-type drain extension region connecting said lateral channel to a common drain electrode, a vertically-extended source extension region connecting said source region to a common source electrode on the backside of the device, and a shorting strap connecting the source region to the vertically-extended source extension region;
- wherein both said gate electrodes are electrically separate portions of a single thin film layer;
- wherein the threshold voltage of said first laterally-gated transistor is less than the threshold voltage of said second laterally-gated transistor;
- and wherein said vertically-extended source extension regions are a single common region which laterally separates said first and second laterally-gated transistors.
Dependencies are inferred from the claim text.