Bidirectional power transistor with shallow body trench

摘要

A bi-directional trench field effect power transistor. A layer stack extends over the top surface of the substrate, in which vertical trenches are present. An electrical path can be selectively enabled or disabled to allow current to flow in opposite directions through a body located laterally between the first and second vertical trenches. A shallow trench, more shallow than the first vertical trench and the second vertical trench is located between the first vertical trench and the second vertical trench and extend in the vertical direction from the top layer of the stack into the body, beyond an upper boundary of the body. The body is provided with a dopant, the concentration of the dopant is at least one order of magnitude higher in a region adjacent to the shallow trench than near the first vertical trench and the second vertical trench.

主权项

1. A bi-directional trench field effect power transistor, comprising:
a substrate with a substrate top surface; a layer stack extending over the substrate top surface, in which stack a first vertical trench and a second vertical trench are present, each of said vertical trenches extending in a vertical direction from a top layer of the stack towards the substrate; a first current terminal and a second current terminal, the first current terminal being situated, in said vertical direction, below the second current terminal and the second current terminal being situation on or above the top layer; and an electrical path which can be selectively enabled or disabled to allow current to flow in a first direction or a second direction, opposite to the first direction, between the first current terminal and the second current terminal, the electrical path comprising: a body located laterally between the first and second vertical trenches and vertically between said first current terminal and said second current terminal; a first drift region located, in said vertical direction, between the body and the first current terminal; a second drift region located, in said vertical direction, between the body and the second current terminal; a shallow trench, more shallow than the first vertical trench and the second vertical trench, the shallow trench being located between the first vertical trench and the second vertical trench and extending in the vertical direction from the top layer of the stack into the body, beyond an upper boundary of the body; and the body is provided with a dopant, the concentration of said dopant being at least one order of magnitude higher in a region adjacent to the shallow trench than near the first vertical trench and the second vertical trench.