Integrated lateral high-voltage diode and thyristor
View Patent ↗The present invention relates to integration of lateral high-voltage devices, such as a lateral high-voltage diode (LHVD) or a lateral high-voltage thyristor, with other circuitry on a semiconductor wafer, which may be fabricated using low-voltage foundry technology, such as a low-voltage complementary metal oxide semiconductor (LV-CMOS) process. The other circuitry may include low-voltage devices, such as switching transistors used in logic circuits, computer circuitry, or the like, or other high-voltage devices, such as a microelectromechanical system (MEMS) switch. The reverse breakdown voltage capability of the LHVD may be increased by using an intrinsic material between the anode and the cathode. Similarly, in a lateral high-voltage thyristor, such as a lateral high-voltage Silicon-controlled rectifier (LHV-SCR), the withstand voltage capability of the LHV-SCR may be increased by using an intrinsic material between the anode and the cathode.
1. A Silicon-on-insulator (SOI) semiconductor wafer comprising:
an SOI insulator layer;
an SOI device layer formed over the SOI insulator layer comprising;
an anode;
a cathode;
an anode extension extending from the anode toward the SOI insulator layer;
a cathode extension extending from the cathode toward the SOI insulator layer; and
first intrinsic material between the anode and the cathode, such that the first intrinsic material has a resistivity greater than about one ohm•centimeter and the anode, the cathode, and the intrinsic material form a lateral high-voltage diode (LHVD).
2. The SOI semiconductor wafer of claim 1 wherein a reverse breakdown voltage between the anode and the cathode is greater than about 20 volts.
3. The SOI semiconductor wafer of claim 1 wherein a reverse breakdown voltage between the anode and the cathode is greater than about 50 volts.
4. The SOI semiconductor wafer of claim 1 wherein the LHVD is laterally isolated from at least one other device in the SOI device layer using deep trench isolation.
5. The SOI semiconductor wafer of claim 1 wherein the LHVD is used in a charge pump circuit.
6. The SOI semiconductor wafer of claim 1 wherein the LHVD is used in an input protection circuit.
7. The SOI semiconductor wafer of claim 1 wherein the anode, the cathode, and the first intrinsic material are formed using low-voltage foundry technology.
8. The SOI semiconductor wafer of claim 1 wherein the anode extension further extends from the anode toward the first intrinsic material and the cathode extension further extends from the cathode toward the first intrinsic material.
9. The SOI semiconductor wafer of claim 1 wherein:
the cathode comprises N-type semiconductor material having a first carrier concentration;
the cathode extension comprises the N-type semiconductor material having a second carrier concentration, which is less than the first carrier concentration;
the anode comprises P-type semiconductor material having a third carrier concentration; and
the anode extension comprises the P-type semiconductor material having a fourth carrier concentration, which is less than the third carrier concentration.
10. The SOI semiconductor wafer of claim 9 wherein:
the first carrier concentration is greater than about 10 18 cm −3 ;
the second carrier concentration is less than about 10 18 cm −3 ;
the third carrier concentration is greater than about 10 18 cm −3 ; and
the fourth carrier concentration is less than about 10 18 cm −3 .