Lateral transistors and methods with low-voltage-drop shunt to body diode
First Claim
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1. 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
shielding shapes interposed between the gate electrodes of said laterally-gated transistors.
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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.
6 Citations
10 Claims
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1. A power semiconductor device, comprising:
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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 shielding shapes interposed between the gate electrodes of said laterally-gated transistors. - View Dependent Claims (2, 3)
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4. A power semiconductor device, comprising:
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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, and a vertically-extended source extension region connecting said source region to a common source electrode on the backside of the device; 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; wherein the gate electrode of said first laterally-gated transistor, but not the gate electrode of said second laterally-gated transistor, is connected to said common source electrode; and wherein said vertically-extended source extension regions are a single common region which laterally separates said first and second laterally-gated transistors.
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5. A power semiconductor device, comprising:
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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, and a vertically-extended source extension region connecting said source region to a common source electrode on the backside of the device; 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; wherein the gate electrode of said first laterally-gated transistor, but not the gate electrode of said second laterally-gated transistor, is connected to said common source electrode. - View Dependent Claims (6, 7, 8, 9, 10)
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Specification