High voltage composite semiconductor device with protection for a low voltage device
View Patent ↗There are disclosed herein various implementations of composite semiconductor devices including a voltage protected device. In one exemplary implementation, a normally OFF composite semiconductor device comprises a normally ON III-nitride power transistor having a first output capacitance, and a low voltage (LV) device cascoded with the normally ON III-nitride power transistor to form the normally OFF composite semiconductor device, the LV device having a second output capacitance. A ratio of the first output capacitance to the second output capacitance is set based on a ratio of a drain voltage of the normally ON III-nitride power transistor to a breakdown voltage of the LV device so as to provide voltage protection for the LV device.
1. A normally OFF composite semiconductor device, comprising:
a normally ON III-nitride power transistor having a first output capacitance;
a low voltage (LV) device cascoded with said normally ON III-nitride power transistor to form said normally OFF composite semiconductor device, said LV device having a second output capacitance;
said first output capacitance and said second output capacitance being designed to satisfy a first ratio set according to a second ratio of a drain voltage of said normally ON III-nitride power transistor to a breakdown voltage of said LV device so as to provide voltage protection for said LV device;
said normally ON III-nitride power transistor configured to turn OFF in response to a voltage across said LV device,
wherein said first ratio is set to less than 120.
2. The normally OFF composite semiconductor device of claim 1 , wherein said normally ON III-nitride power transistor is one of a III-nitride field-effect transistor (III-N FET) and a III-nitride high electron mobility transistor (III-N HEMT).
3. The normally OFF composite semiconductor device of claim 1 , wherein said LV device comprises an LV group IV semiconductor device.
4. The normally OFF composite semiconductor device of claim 1 , wherein said LV device comprises an LV silicon device.
5. The normally OFF composite semiconductor device of claim 1 , wherein said LV device comprises an LV field-effect transistor (LV FET).
6. The normally OFF composite semiconductor device of claim 1 , wherein said LV device is one of an LV metal-oxide-semiconductor FET (LV MOSFET) and an LV metal-insulator-semiconductor FET (LV MISFET).
7. The normally OFF composite semiconductor device of claim 1 , wherein said LV device comprises an LV diode.
8. The normally OFF composite semiconductor device of claim 1 , wherein said normally ON III-nitride power transistor and said LV device are monolithically integrated.
9. A normally OFF composite semiconductor device, comprising: a normally ON III-nitride power transistor having a first output capacitance; a low voltage (LV) device cascaded with said normally ON III-nitride power transistor to form said normally OFF composite semiconductor device, said LV device having a drain and a second output capacitance, wherein a ratio of said first output capacitance to said second output capacitance is based on a drain voltage of said normally ON III-nitride power transistor and a breakdown voltage of said LV device, and set to ensure that a voltage at said drain of the LV device does not rise beyond said breakdown voltage of said LV device, wherein said normally ON III-nitride power transistor is configured to, and turn OFF in response to a voltage across said LV device, and wherein said ratio is set to less than 120.
10. The normally OFF composite semiconductor device of claim 9 , wherein said normally ON III-nitride power transistor is one of a III-nitride field-effect transistor (III-N FET) and a III-nitride high electron mobility transistor (III-N HEMT).
11. The normally OFF composite semiconductor device of claim 9 , wherein said LV device comprises an LV group IV semiconductor device.
12. The normally OFF composite semiconductor device of claim 9 , wherein said LV device comprises an LV silicon device.
13. The normally OFF composite semiconductor device of claim 9 , wherein said LV device comprises an LV field-effect transistor (LV FET).
14. The normally OFF composite semiconductor device of claim 9 , wherein said LV device is one of an LV metal-oxide-semiconductor FET (LV MOSFET) and an LV metal-insulator-semiconductor FET (LV MISFET).
15. The normally OFF composite semiconductor device of claim 9 , wherein said LV device comprises an LV diode.
16. The normally OFF composite semiconductor device of claim 9 , wherein said normally ON III-nitride power transistor and said LV device are monolithically integrated.