High voltage device
View Patent ↗A method of forming a device is presented. The method includes providing a substrate prepared with an active device region. The active device region includes gate stack layers of a gate stack including at least a gate electrode layer over a gate dielectric layer. A first mask is provided on the substrate corresponding to the gate. The substrate is patterned to at least remove portions of a top gate stack layer unprotected by the first mask. A second mask is also provided on the substrate with an opening exposing a portion of the first mask and the top gate stack layer. A channel well is formed by implanting ions through the opening and gate stack layers into the substrate.
1. A method of forming a device comprising:
providing a substrate prepared with an active device region, wherein the active device region includes gate stack layers of a gate stack comprising at least a gate electrode layer over a gate dielectric layer;
providing a first mask on the substrate corresponding to the gate;
patterning the substrate to at least remove portions of a top gate stack layer unprotected by the first mask;
providing a second mask on the substrate with an opening exposing a portion of the first mask and the top gate stack layer; and
implanting ions through the opening and gate stack layers into the substrate to form a channel well.
2. The method of claim 1 wherein the top gate stack layer comprises the gate electrode layer of the gate stack.
3. The method of claim 2 wherein the gate electrode layer comprises silicon, including amorphous or polysilicon.
4. The method of claim 2 wherein the first mask comprises a hard mask.
5. The method of claim 4 wherein a first edge of the gate corresponds to a channel edge of the gate of the device and a second edge of the gate corresponds to the drain edge of the gate of the device.
6. The method of claim 1 wherein the first edge of the gate corresponds to a channel edge of the gate of the device and the second edge of the gate corresponds to the drain edge of the gate of the device.
7. The method of claim 1 wherein patterning the substrate leaves the gate dielectric layer remaining on the substrate.
8. The method of claim 1 wherein patterning the gate stack layers leaves the gate dielectric layer remaining on the substrate.
9. The method of claim 1 wherein implanting ions comprises a tilt angle implant.
10. The method of claim 1 wherein a tilt angle of the implant is about 1-45°.
11. The method of claim 1 wherein implanting ions comprises multiple tilt angle implants which are rotated about a plane of the substrate.
12. The method of claim 11 wherein a tilt angle of the implant is about 1-45°.
13. The method of claim 1 wherein implanting ions comprises a quad tilt angle implant which is rotated about a plane of the substrate.
14. The method of claim 1 wherein the second mask comprises photoresist.
15. The method of claim 14 wherein the first mask comprises a hard mask.
16. The method of claim 15 wherein a first edge of the gate corresponds to a channel edge of the gate of the device and a second edge of the gate corresponds to the drain edge of the gate of the device.
17. A method of forming a device comprising:
providing a substrate prepared with an active device region which includes a doped drift well in a first portion of the active device region and gate stack layers of a gate stack comprising at least a gate electrode layer over a gate dielectric layer on the surface of the substrate;
providing a first mask on the substrate corresponding to the gate;
patterning the substrate to at least remove portions of a top gate stack layer unprotected by the first mask;
providing a second mask on the substrate with an opening exposing a portion of the first mask and the top gate stack layer; and
implanting ions through the opening and gate stack layers into the substrate to form a channel well.
18. The method of claim 17 wherein the substrate comprises:
a drift isolation region in the doped drift well; and
a doped deep well in the substrate of the active device region encompassing the doped drift well.