Semiconductor Device and Associated Method
The invention relates to a semiconductor device and an associated method for fabricating the semiconductor device. The device comprises: a substrate having a contact surface and a back surface separated by a total distance; a vertical device formed in the substrate and having first and second terminals on the contact surface; an isolation trench extending the total distance through the substrate between the contact surface and the back surface to electrically isolate the vertical device; and a terminal separation trench extending from the contact surface into the substrate and arranged to separate and define an electrical conduction path between the first and second terminals of the vertical device.
1 . A semiconductor device comprising:
a substrate having a contact surface and a back surface separated by a total distance;
a vertical device formed in the substrate and having first and second terminals on the contact surface;
an isolation trench extending the total distance through the substrate between the contact surface and the back surface to electrically isolate the vertical device; and
a terminal separation trench extending from the contact surface into the substrate and arranged to separate, and define an electrical conduction path between, the first and second terminals of the vertical device.
2 . The semiconductor device of claim 1 comprising a second device on an opposing side of the isolation trench to the vertical device.
3 . The semiconductor device of claim 2 wherein the isolation trench electrically isolates the vertical device from the second device.
4 . The semiconductor device of claim 1 wherein the isolation trench is continuous and form an island of substrate on which the vertical device is provided.
5 . The semiconductor device of claim 1 wherein the vertical device comprises a vertical transistor or vertical diode.
6 . The semiconductor device of claim 1 wherein an electrically insulating and thermally conductive material is provided on the back surface.
7 . The semiconductor device of claim 1 wherein the isolation trench and terminal separation trench each comprises a dielectric material.
8 . The semiconductor device of claim 1 wherein the electrical conduction path is at least partially defined by a metallic material provided within the substrate.
9 . A method of fabricating a semiconductor device, comprising:
receiving a substrate having a contact surface with a vertical device formed in the substrate and having a first terminal on the contact surface;
forming an isolation trench extending a first distance through the substrate for electrically isolating the vertical device; and
forming a terminal separation trench extending from the contact surface into the substrate, the terminal separation trench arranged to define a second terminal of the vertical device on the contact surface and to define an electrical conduction path between first and second terminals.
10 . The method of claim 9 wherein the isolation trench is a first isolation trench and the method comprises forming a second isolation trench on an opposing side of the vertical device to the first isolation trench, each of the first and second isolation trenches arranged to electrically isolate the transistor.
11 . The method of claim 9 wherein the substrate has a back surface separated by a total distance from the contact surface.
12 . The method of claim 11 wherein forming the isolation trench comprises removing substrate material from the back surface.
13 . The method of claim 12 wherein forming the isolation trench comprises, subsequent to removing substrate material from the back surface, removing substrate material from the contact surface.
14 . The method of claim 9 comprising reducing a thickness of the substrate from the initial thickness to a final product thickness to form a back surface opposing the contact surface.
15 . The method of claim 9 wherein the isolation trench and terminal separation trench are each formed during the same processing step.