Vertically pinched junction field effect transistor

1. A junction field-effect transistor comprising:

a semiconductor substrate;

a source region and a drain region in the semiconductor substrate;

a main-channel region formed between the source region and the drain region;

a well region formed on the main-channel region between the source region and the drain region;

vertical pinch-off regions formed at both ends of the well region on the main-channel region in the source region and the drain region respectively;

a source contact on the vertical pinch-off region in the source region;

a drain contact on the vertical pinch-off region in the drain region;

a gate contact on the well region between the source contact and the drain contact; and

shallow trench isolations formed on the well region and configured to isolate the source contact, the drain contact, and the gate contact from each other.

2. The junction field-effect transistor of claim 1 , wherein the vertical pinch-off regions are independent elements separated from the main-channel region.

3. The junction field-effect transistor of claim 2 , wherein the vertical pinch-off regions are configured to contact the source region, the drain region, the gate contact and the well region.

4. The junction field-effect transistor of claim 2 , wherein the vertical pinch-off regions electrically connect the main-channel region and the source contact and the drain contact.

5. The junction field-effect transistor of claim 1 , wherein a conductivity type of the main-channel region is an n-type, a conductivity type of the well region is a p-type, and the vertical pinch-off regions are lightly-doped n-type region.

6. The junction field-effect transistor of claim 1 , wherein the well region is configured to act as a gate and is connected to the gate contact.

7. The junction field-effect transistor of claim 1 , wherein the main-channel region is electrically connected through the vertical pinch-off regions.

8. The junction field-effect transistor of claim 1 , wherein the main-channel region is formed by implanting a deep n-type well.

9. The junction field-effect transistor of claim 1 , wherein the main-channel region is formed by forming a highly-doped n type buried layer.

10. The junction field-effect transistor of claim 1 , wherein the source region and the drain region each have a conductivity type identical to that of the vertical pinch-off regions and the main-channel region.

11. The junction field-effect transistor of claim 1 , wherein the well region has a conductivity type different from that of the source region and the drain region.

12. The junction field-effect transistor of claim 1 , further comprising a silicon-on-insulator layer under the semiconductor substrate.

13. The junction field-effect transistor of claim 12 , wherein the silicon-on-insulator layer comprises a buried oxide layer.

14. The junction field-effect transistor of claim 1 , further comprising silicide blocks formed between the gate contact and the source contact and between the gate contact and the drain contact.

15. The junction field-effect transistor of claim 14 , wherein the gate contact, the source contact, and the drain contact are separated by the silicide blocks.

16. The junction field-effect transistor of claim 1 , wherein the junction field-effect transistor has a current-carrying capability larger than about 500 μA per μm width.

17. An apparatus comprising:

a semiconductor substrate having a source region and a drain region;

a silicon-on-insulator layer under the semiconductor substrate;

a main-channel region formed between the source region and the drain region;

a well region formed on the main-channel region between the source region and the drain region;

vertical pinch-off regions formed at one of both source and drain ends and only at the source-end of the well region on the main-channel region in the source region and the drain region respectively;

a source contact on the vertical pinch-off region in the source region;

a drain contact on the vertical pinch-off region in the drain region;

a gate contact on the well region between the source contact and the drain contact; and

silicide blocks formed between the gate contact and the source contact and between the gate contact and the drain contact and configured to separate the gate contact, the source contact, and the drain contact from each other.

18. The apparatus of claim 17 , wherein the apparatus comprises a junction field-effect transistor.

19. An apparatus comprising:

a semiconductor substrate having a source region and a drain region;

a silicon-on-insulator layer under the semiconductor substrate;

a main-channel region formed between the source region and the drain region;

a well region formed on the main-channel region between the source region and the drain region;

vertical pinch-off regions formed at one of both source and drain ends and only at the source-end end of the well region on the main-channel region in the source region and the drain region respectively;

a source contact on the vertical pinch-off region in the source region;

a drain contact on the vertical pinch-off region in the drain region;

a gate contact on the well region between the source contact and the drain contact;

shallow trench isolations formed on the well region; and

silicide blocks formed between the gate contact and the source contact and between the gate contact and the drain contact and configured to separate the gate contact, the source contact, and the drain contact from each other,

wherein the vertical pinch-off regions are configured to contact the source region, the drain region, the gate contact and the well region and also electrically connect the main-channel region and the source contact and the drain contact.

20. The apparatus of claim 19 , wherein the apparatus comprises a junction field-effect transistor.