Monolithically integrated HEMT and current protection device
First Claim
1. A transistor device, comprising:
- a high electron mobility field effect transistor (HEMT) having a source, a drain, a gate, and a first insulator separating the gate from a compound semiconductor body of the transistor device, the HEMT operable to switch on and conduct current from the source to the drain when a voltage applied to the gate exceeds a threshold voltage of the HEMT; and
a protection device monolithically integrated with the HEMT so that the protection device shares the source and the drain with the HEMT and further comprises a gate electrically connected to the source and a second insulator separating the gate of the protection device from the compound semiconductor body, the protection device operable to conduct current from the drain to the source when the HEMT is switched off and a reverse voltage between the source and the drain exceeds a threshold voltage of the protection device, the threshold voltage of the protection device being less than the difference of the threshold voltage of the HEMT and a gate voltage used to turn off the HEMT,wherein the first insulator is thinner under the gate of the HEMT than the second insulator under the gate of the protection device.
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Accused Products
Abstract
A transistor device includes a high electron mobility field effect transistor (HEMT) and a protection device. The HEMT has a source, a drain and a gate. The HEMT switches on and conducts current from the source to the drain when a voltage applied to the gate exceeds a threshold voltage of the HEMT. The protection device is monolithically integrated with the HEMT so that the protection device shares the source and the drain with the HEMT and further includes a gate electrically connected to the source. The protection device conducts current from the drain to the source when the HEMT is switched off and a reverse voltage between the source and the drain exceeds a threshold voltage of the protection device. The protection device has a lower threshold voltage than the difference of the threshold voltage of the HEMT and a gate voltage used to turn off the HEMT.
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Citations
25 Claims
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1. A transistor device, comprising:
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a high electron mobility field effect transistor (HEMT) having a source, a drain, a gate, and a first insulator separating the gate from a compound semiconductor body of the transistor device, the HEMT operable to switch on and conduct current from the source to the drain when a voltage applied to the gate exceeds a threshold voltage of the HEMT; and a protection device monolithically integrated with the HEMT so that the protection device shares the source and the drain with the HEMT and further comprises a gate electrically connected to the source and a second insulator separating the gate of the protection device from the compound semiconductor body, the protection device operable to conduct current from the drain to the source when the HEMT is switched off and a reverse voltage between the source and the drain exceeds a threshold voltage of the protection device, the threshold voltage of the protection device being less than the difference of the threshold voltage of the HEMT and a gate voltage used to turn off the HEMT, wherein the first insulator is thinner under the gate of the HEMT than the second insulator under the gate of the protection device. - View Dependent Claims (2, 3)
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4. A DC-to-DC converter, comprising:
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a high-side transistor for coupling to a load; a low-side high electron mobility field effect transistor (HEMT) for coupling to the load; and a protection device monolithically integrated with the low-side HEMT in a compound semiconductor body so that the protection device shares a source and a drain with the low-side HEMT and further comprises a gate electrically connected to the source, the protection device operable to conduct current between the drain and the source when the low-side HEMT is switched off, the high-side HEMT is switched off and a reverse voltage between the source and the drain exceeds a threshold voltage of the protection device, the threshold voltage of the protection device being less than the difference of the threshold voltage of the HEMT and a gate voltage used to turn off the HEMT, wherein a first insulator separating a gate of the HEMT from the compound semiconductor body is thinner than a second insulator separating the gate of the protection device from the compound semiconductor body. - View Dependent Claims (5)
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6. A semiconductor device, comprising:
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a compound semiconductor body; a high electron mobility field effect transistor (HEMT) comprising a source extending into the compound semiconductor body, a drain spaced apart from the source and extending into the compound semiconductor body, a gate disposed in a first trench extending into the compound semiconductor body, and a first insulator separating the gate from the compound semiconductor body in the first trench; a protection device comprising a source common with the source of the HEMT, a drain common with the drain of the HEMT, a gate disposed in a second trench extending into the compound semiconductor body and electrically connected to the source, and a second insulator separating the gate of the protection device from the compound semiconductor body in the second trench; and wherein at least one of the first insulator is thinner in the first trench than the second insulator in the second trench and the first trench extends deeper into the compound semiconductor body than the second trench. - View Dependent Claims (7, 8, 9, 10, 11, 12, 13, 14)
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15. A method of manufacturing a semiconductor device, comprising:
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forming a high electron mobility field effect transistor (HEMT) in a compound semiconductor body, the HEMT comprising a source extending into the compound semiconductor body, a drain spaced apart from the source and extending into the compound semiconductor body, a gate disposed in a first trench extending into the compound semiconductor body, and a first insulator separating the gate from the compound semiconductor body in the first trench; and monolithically integrating a protection device with the HEMT so that the protection device has a source common with the source of the HEMT, a drain common with the drain of the HEMT, a gate disposed in a second trench extending into the compound semiconductor body and electrically connected to the source, a second insulator separating the gate of the protection device from the compound semiconductor body in the second trench, and at least one of the first insulator is thinner in the first trench than the second insulator in the second trench and the first trench extends deeper into the compound semiconductor body than the second trench. - View Dependent Claims (16, 17, 18, 19, 20, 21, 22, 23, 24, 25)
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Specification