Fuji Electric Holdings Co., Ltd.

Shin-etsu Handotai Co., Ltd.

Daisuke Kishimoto

Katsunori Ueno

Susumu Iwamoto

Satoshi Oka

Akihiko Ohi

Yoshihiko Nagayasu

Hitoshi Kuribayashi

Ryohsuke Shimizu

Yuji Sano

In the method for manufacturing a semiconductor device according to the invention including the step of forming trenches having the depth thereof in perpendicular to the major surface of a semiconductor substrate, the step of forming trenches includes the steps of performing trench etching using an insulator film, formed on the major surface of the semiconductor substrate and shaped with a predetermined pattern, for a mask to form the trenches; etching the inside of the trenches using a halogen containing gas to smoothen the inside of the trenches; and thermally treating in a non-oxidizing and non-nitriding atmosphere. The manufacturing method according to the invention facilitates well removing the etching residues remaining in the trenches and rounding the trench corners properly when the trenches are 2 &#x3bc;m or narrower in width and even when the trenches are 1 &#x3bc;m or narrower in width.

Method for manufacturing a semiconductor device having trenches defined in the substrate surface

A semiconductor superjunction device has a superjunction structure formed in a drift region of the device. The superjunction structure has alternately arranged n-type regions and p-type semiconductor regions layered parallel with the drift direction of carriers, permitting current flow when turned ON and depleting when turned OFF. It also includes a first intrinsic semiconductor region between the n-type and p-type regions. The first intrinsic semiconductor region and the n-type and p-type regions sandwiching the first intrinsic semiconductor region forming a unit. A plurality of units are repetitively arranged to form a repetitively arranged structure. The value of mobility of one of electrons in the n-type region or holes in the p-type region is equal to or less than half the value of mobility of corresponding to one of electrons or holes in the first intrinsic semiconductor region. The superjunction structure eliminates the lower limit that prevents further narrowing of the widths of the n-type and p-type regions to further improve the tradeoff relationship between increasing the breakdown voltage and reducing the on-resistance.

Semiconductor superjunction device

A fabrication method of a semiconductor wafer can fill trenches formed in a semiconductor substrate with an epitaxial film with high crystal quality without leaving cavities in the trenches. The trenches are formed in the first conductivity type semiconductor substrate. Planes exposed inside the trenches are made clean surfaces by placing the substrate in a gas furnace, followed by supplying the furnace with an etching gas and carrier gas, and by performing etching on the exposed planes inside the trenches by a thickness from about a few nanometers to one micrometer. The trenches have a geometry opening upward through the etching. Following the etching, a second conductivity type semiconductor is epitaxially grown in the trenches by supplying the furnace with a growth gas, etching gas, doping gas and carrier gas, thereby filling the trenches. Instead of making the trenches slightly-opened upward, their sidewalls may be made planes enabling facet formation.

Fabrication method of semiconductor wafer

Growing community of inventors

Nagano, Japan

Daisuke Kishimoto