Method for forming a superjunction device with improved ruggedness
First Claim
Patent Images
1. A method for forming a superjunction device on a substrate having a first conductivity type, the method comprising:
- forming a plurality of horizontal first layers of semiconductor material over the substrate, the first layers of semiconductor material being of the first conductivity type, wherein a first layer of said plurality of horizontal first layers is below a second layer of said plurality of horizontal first layers; and
diffusing semiconductor material of a second conductivity type in a plurality of vertically aligned regions on each of the first and second layers, the plurality of vertically aligned regions forming spaced pylons whose widths are narrower than a distance between two adjacent pylons, wherein the vertically aligned regions of the second layer are laterally wider than the vertically aligned regions of the first layer, and wherein a plurality of respective top surfaces of the vertically aligned regions of the second layer are below active regions of the superjunction device.
0 Assignments
0 Petitions
Accused Products
Abstract
An improved superjunction semiconductor device includes a charged balanced pylon in a body region, where a top of the pylon is large to create slight charge imbalance. A MOSgated structure is formed over the top of the pylon and designed to conduct current through the pylon. By increasing a dimension of the top of the pylon, the resulting device is less susceptible to variations in manufacturing tolerances to obtain a good breakdown voltage and improved device ruggedness.
-
Citations
20 Claims
-
1. A method for forming a superjunction device on a substrate having a first conductivity type, the method comprising:
-
forming a plurality of horizontal first layers of semiconductor material over the substrate, the first layers of semiconductor material being of the first conductivity type, wherein a first layer of said plurality of horizontal first layers is below a second layer of said plurality of horizontal first layers; and diffusing semiconductor material of a second conductivity type in a plurality of vertically aligned regions on each of the first and second layers, the plurality of vertically aligned regions forming spaced pylons whose widths are narrower than a distance between two adjacent pylons, wherein the vertically aligned regions of the second layer are laterally wider than the vertically aligned regions of the first layer, and wherein a plurality of respective top surfaces of the vertically aligned regions of the second layer are below active regions of the superjunction device. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
-
-
9. A method for forming a superjunction device having improved avalanche capability, the method comprising:
-
forming a layer of semiconductor material on a substrate, the substrate and the layer being of N-type conductivity and comprises a plurality of horizontal portions, wherein a first portion of said plurality of horizontal portions is below a second portion of said plurality of horizontal portions; diffusing semiconductor material of P-type conductivity in a plurality of vertically aligned regions in the layer, the plurality of vertically aligned regions forming spaced pylons whose widths are narrower than a distance between two adjacent pylons and length equals that of the width of the layer, wherein an area of each pylon farthest from the substrate and constituting a portion of the total area of the pylon, are laterally wide than the rest of the pylon, wherein a top surface of the area of each pylon farthest from the substrate is below an associated active region of the superjunction device. - View Dependent Claims (10, 11, 12)
-
-
13. A method for forming a superjunction device, comprising:
-
providing a substrate having one conductivity type; overlaying the substrate with a semiconductor material having the same conductivity type to form a first layer comprising a plurality of horizontal portions, wherein a first portion of said plurality of horizontal portions is below a second portion of said plurality of horizontal portions; diffusing a semiconductor material of the other conductivity type into the first layer to form a first implant; forming a second layer over the first layer having the one conductivity type; diffusing a semiconductor material of the other conductivity type into the second layer to form a second implant laterally wider than that of the first implant, wherein a first portion of the semiconductor material of the other conductivity type forms a first pylon whose width is narrower than a distance between the first pylon and a second portion of the semiconductor material of the other conductivity type forming a second pylon, wherein a top surface of the semiconductor material of the other conductivity type diffused into the second layer is below an active region of the superjunction device. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20)
-
Specification