Bootstrap field effect transistor (FET)
View Patent ↗A laterally diffused metal oxide semiconductor (LDMOS) device, and a method of manufacturing the same are provided. The LDMOS device can include a drain region of a bootstrap field effect transistor (FET), a source region of the bootstrap FET, a drift region formed between the drain region and the source region, and a gate formed at one side of the source region and on the drift region.
1. A laterally diffused metal oxide semiconductor (LDMOS) device, comprising:
a drain region of a bootstrap field effect transistor (FET);
a source region of the bootstrap FET;
a drift region between the drain region and the source region;
a gate at one side of the source region and on the drift region;
a first conductive type epitaxial layer on a second conductive type semiconductor substrate having a first P-TOP region between a second conductive type deep well and a first conductive type first well; and
a field insulating layer on the first conductive type epitaxial layer;
wherein the drain region comprises (i) a first conductive type first buried layer on the second conductive type semiconductor substrate, (ii) the first conductive type first well on the first conductive type first buried layer; and (iii) a high concentration first conductive type first connection region in the first conductive type first well, and the source region comprises (i) a second conductive type buried layer on the second conductive type semiconductor substrate, (ii) the second conductive type deep well on the second conductive type buried layer, (iii) a first conductive type second well and a second conductive type first well in the second conductive type deep well; and (iv) a high concentration first conductive type second connection region in the first conductive type second well.
2. The LDMOS device according to claim 1 , wherein the source region of the bootstrap transistor is connected to a bootstrap capacitor, and a driving voltage is applied to the drain region.
3. The LDMOS device according to claim 1 , wherein the drift region comprises a field insulating layer on the first P-TOP region.
4. The LDMOS device according to claim 3 , further comprising a second P-TOP region at one end of the gate.
5. The LDMOS device according to claim 1 , further comprising a diode electrically connected to the source region.
6. The LDMOS device according to claim 1 , wherein the gate is a polysilicon gate.
7. The LDMOS device according to claim 1 , wherein the first conductive type is an N-type and the second conductive type is a P-type.
8. The LDMOS device according to claim 1 , further comprising:
a second P-TOP region at one side of the first conductive type second well and under the gate;
a first electrode electrically connected to the high concentration first conductive type first connection region of the drain region;
a second electrode electrically connected to the gate; and
a third electrode electrically connected to the high concentration first conductive type second connection region of the source region.
9. The LDMOS device according to claim 8 , further comprising a diode at one side of the source region, wherein the diode comprises:
a first conductive type second buried layer on the semiconductor substrate;
a first conductive type first deep well, a second conductive second deep well, and a first conductive type second deep well in the first conductive type epitaxial layer over the first conductive type second buried layer;
a second conductive type second well, a first conductive type third well, and a second conductive type third well in the second conductive type second deep well;
a high concentration second conductive type first connection region in the second conductive type second well;
a high concentration first conductive type third connection region in the first conductive type third well;
a high concentration second conductive type second connection region in the second conductive type third well; and
a high concentration first conductive type fourth connection region in the first conductive type second deep well.
10. The LDMOS device according to claim 9 , further comprising a fourth electrode electrically connected to the high concentration second conductive type second connection region and the high concentration first conductive type fourth connection region,
wherein the high concentration first conductive type third connection region is electrically connected to the third electrode.
11. The LDMOS device according to claim 10 , wherein the first conductive type is an N-type and the second conductive type is a P-type.
12. The LDMOS device according to claim 1 , wherein the drain region, the source region, and the gate form the bootstrap field effect transistor (FET).
13. The LDMOS device according to claim 1 , wherein the LDMOS device is an n-type LDMOS (nLDMOS) device.
14. The LDMOS device according to claim 13 , wherein the nLDMOS device is on the first conductive type first buried layer and the second conductive type buried layer.
15. The LDMOS device according to claim 1 , wherein the first P-TOP region is on the semiconductor substrate.
16. The LDMOS device according to claim 1 , wherein the field insulating layer comprises a plurality of local oxidation of silicon (LOCOS) layers.
17. The LDMOS device according to claim 6 , wherein the polysilicon gate is in part on the field insulating layer and over the first P-TOP region.
18. The LDMOS device according to claim 1 , wherein the gate polysilicon covers a portion of the source region and a portion of the field insulating layer.
19. The LDMOS device according to claim 1 , wherein the drain region comprises a polysilicon electrode at a side of the field insulating layer opposite from the polysilicon gate.