Alpha and Omega Semiconductor (cayman) Ltd.

Alpha and Omega Semiconductor International LP

Lei Zhang

Madhur Bobde

Hongyong Xue

Lingpeng Guan

Wenjun Li

Jian Wang

Karthik Padmanabhan

Sik Lui

Lingbing Chen

Chris Wiebe

Brian Schorr

Wim Aarts

Xiaobin Wang

Runtao Ning

A device and a method of making the device comprising, a semiconductor substrate layer and an epitaxial layer formed on the semiconductor substrate. One or more trenches are formed in the epitaxial layer, each trench having a pair of opposing sidewalls, wherein a distance between the opposing sidewalls is greater near a bottom of the trench than near a top of the trench, wherein the bottom of the trench is closer to the semiconductor substrate layer than the top.

High density shield gate transistor structure and method of making

An improved inverted field-effect-transistor semiconductor device and method of making thereof may comprise a source layer on a bottom and a drain disposed on a top of a semiconductor substrate and a vertical current conducting channel between the source layer and the drain controlled by a trench gate electrode disposed in a gate trench lined with an insulating material. A heavily doped drain region is disposed near the top of the substrate surrounding an upper portion of a shield trench and the gate trench. A doped body contact region is disposed in the substrate and surrounding a lower portion of the shield trench. A shield electrode extends upward from the source layer in the shield trench for electrically shorting the source layer and the body region wherein the shield structure extends upward to a heavily doped drain region and is insulated from the heavily doped drain region to act as a shield electrode.

Bottom source trench MOSFET with shield electrode

A semiconductor device includes a semiconductor body having a base region incorporating a field stop zone where the base region and the field stop zone are both formed using an epitaxial process. Furthermore, the epitaxial layer field stop zone is formed with an enhanced doping profile to realize improved soft-switching performance for the semiconductor device. In some embodiments, the enhanced doping profile includes multiple doped regions with peak doping levels where a first doped region adjacent to a first side of the field stop zone has a first peak doping level that is not higher than a last peak doping level of a last doped region adjacent to the base region. The epitaxial layer field stop zone of the present invention enables complex field stop zone doping profiles to be used to obtain the desired soft-switching characteristics in the semiconductor device.

Semiconductor device incorporating epitaxial layer field stop zone

A semiconductor device includes a semiconductor body having a base region incorporating a field stop zone where the base region and the field stop zone are both formed using an epitaxial process. Furthermore, the epitaxial layer field stop zone is formed with an enhanced doping profile to realize improved soft-switching performance for the semiconductor device. In some embodiments, the enhanced doping profile formed in the field stop zone includes varying, non-constant doping levels. In some embodiments, the enhanced doping profile includes one of an extended graded doping profile, a multiple stepped flat doping profile, or a multiple spike doping profile. The epitaxial layer field stop zone of the present invention enables complex field stop zone doping profiles to be used to obtain the desired soft-switching characteristics in the semiconductor device.

A method comprises the steps of providing a semiconductor device wafer; forming a first plurality of alignment marks on a first side of the semiconductor device wafer; forming a first pattern of a first conductivity type; forming a second plurality of alignment marks on a second side of the semiconductor device wafer; forming a bonded wafer by bonding a carrier wafer to the semiconductor device wafer; forming a third plurality of alignment marks on a free side of the carrier wafer; applying a grinding process; forming a plurality of device structure members; removing the carrier wafer; applying an implanting process and an annealing process; applying a metallization process and applying a singulation process.

Method for precisely aligning backside pattern to frontside pattern of a semiconductor wafer

An RC-IGBT includes a semiconductor body incorporating a field stop zone where the base region and the field stop zone are both formed using an epitaxial process and the field stop zone has an enhanced doping profile to realize improved soft-switching performance for the semiconductor device. In alternate embodiments, RC-IGBT device, including the epitaxial layer field stop zone, are realized through a fabrication process that uses front side processing only to form the backside contact regions and the front side device region. The fabrication method forms an RC-IGBT device using front side processing to form the backside contact regions and then using wafer bonding process to flip the semiconductor structure onto a carrier wafer so that front side processing is used again to form the device region.

Reverse conducting IGBT incorporating epitaxial layer field stop zone

A trench metal-oxide-semiconductor field-effect transistor (MOSFET) device includes a combination of shielded trench gate structure and a superjunction structure within an epitaxial layer including alternating n-doped and p-doped columns in an a drift region. In one example the gate trenches are formed in and over n-doped columns that have an extra charge region near and adjacent to the lower portion of the corresponding gate trench. The extra charge is balanced due to the shield electrodes in the gate trenches.

SGT superjunction MOSFET structure

An RC-IGBT includes a semiconductor body formed having a base region incorporating a field stop zone where the base region and the field stop zone are both formed using an epitaxial process and the field stop zone has an enhanced doping profile to realize improved soft-switching performance for the semiconductor device. In alternate embodiments, RC-IGBT device, including the epitaxial layer field stop zone, are realized through a fabrication process that uses front side processing only to form the backside contact regions and the front side device region. The fabrication method forms an RC-IGBT device using front side processing to form the backside contact regions and then using wafer bonding process to flip the semiconductor structure onto a carrier wafer so that front side processing is used again to form the device region.

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Portland, OR, United States of America

Lei Zhang