Power transistor with increased avalanche current and energy rating

A method comprising:

• (a) forming a drift region;
• (b) forming a body region which extends down into the drift region from a first upper semiconductor surface, wherein the body region meets the drift region at a body-to-drift boundary, wherein the body-to-drift boundary has a central portion, and wherein the central portion of the body-to-drift boundary is non-planar;
• and
• (c) forming a source region which extends down into the body region from a second upper semiconductor surface.

A method comprising:

• (a) forming a poly silicon layer over portions of a drift region, wherein a surface of the drift region is exposed;
• (b) implanting boron into the surface of the drift region that is exposed;
• (c) diffusing the implanted boron into the drift region thereby forming a body region, wherein a surface of the body region is exposed;
• (d) implanting phosphorous into the surface of the body region that is exposed;
• (e) applying a mask to a portion of the surface of the body region that is exposed;
• (f) implanting boron to the surface of the body region that is exposed and not covered by the mask applied in (e);
• and
• (g) diffusing the phosphorus implanted in (d) and the boron implanted in (f), wherein the diffusing of the phosphorus forms a source region, wherein the diffusing of the boron forms a first portion of the body region, and wherein the first portion of the body region has a higher boron concentration than a second portion of the body region.

A method comprising:

• (a) forming a poly silicon layer over portions of a drift region, wherein a surface of the drift region is exposed;
• (b) applying a first boron implantation onto the surface of the drift region that is exposed;
• (c) diffusing the first boron implantation applied in (b) into the drift region such that a body region is formed, wherein a surface of the body region is exposed;
• (d) applying a phosphorous implantation onto the surface of the body region that is exposed;
• (e) applying a second boron implantation onto a portion of the surface of the body region that is exposed;
• and
• (f) diffusing the phosphorous implantation applied in (d) and the second boron implantation applied in (e), wherein the diffusing of the phosphorus implantation forms a source region, wherein the diffusing of the second boron implantation forms a first portion of the body region having a first doping concentration, and wherein a second portion of the body region has a second doping concentration.