Fairchild Semiconductor Corporation

Becky Losee

Dean E Probst

Robert Herrick

Christopher Boguslaw Kocon

Steven Paul Sapp

Bruce Douglas Marchant

James J Murphy

Peter H Wilson

Babak S Sani

Ashok Challa

Alan Elbanhawy

Gordon K Madson

Debra S Woolsey

Hamza Yilmaz

Densen B Cao

Daniel S Calafut

Thomas E Grebs

Gary M Dolny

Rodney S Ridley

Paul Thorup

Duc Q Chau

Christopher Lawrence Rexer

John Mytych

Adam Selsley

A method can include forming a drift region, forming a well region above the drift region, and forming an active trench extending through the well region and into the drift region. The method can include forming a first source region in contact with a first sidewall of the active trench and a second source region in contact with a second sidewall of the active trench. The method also includes forming a charge control trench where the charge control trench is aligned parallel to the active trench and laterally separated from the active trench by a mesa region, and where the portion of the well region is in contact with the charge control trench and excludes any source region. The method also includes forming an oxide along a bottom of the active trench having a thickness greater than a thickness of an oxide along the first sidewall of the active trench.

Methods related to power semiconductor devices with thick bottom oxide layers

A field effect transistor (FET) includes a plurality of trenches extending into a silicon layer, each trench having upper sidewalls that fan out. Contact openings extend into the silicon layer between adjacent trenches such that each trench and an adjacent contact opening form a common upper sidewall portion. Body regions extend between adjacent trenches. Source regions that are self-aligned to corresponding trenches extend in the body regions adjacent opposing sidewalls of each trench, and have a conductivity type opposite that of the body regions.

Power device with self-aligned source regions

In accordance with an embodiment a structure can include a monolithically integrated trench field-effect transistor (FET) and Schottky diode. The structure can include a first gate trench extending into a semiconductor region, a second gate trench extending into the semiconductor region, and a source region flanking a side of the first gate trench. The source region can have a substantially triangular shape, and a contact opening extending into the semiconductor region between the first gate trench and the second gate trench. The structure can include a conductor layer disposed in the contact opening to electrically contact the source region along at least a portion of a slanted sidewall of the source region, and the semiconductor region along a bottom portion of the contact opening. The conductor layer can form a Schottky contact with the semiconductor region.

Field effect transistor and schottky diode structures

A method for forming power semiconductor devices having an inter-electrode dielectric (IPD) layer inside a trench includes providing a semiconductor substrate with a trench, lining the sidewalls and bottom of the trench with a first layer of dielectric material, filling the trench with a first layer of conductive material to form a first electrode, recessing the first layer of dielectric material and the first layer of conductive material to a first depth inside the trench, forming a layer of polysilicon material on a top surface of the dielectric material and conductive material inside the trench, oxidizing the layer of polysilicon material, and forming a second electrode inside the trench atop the oxidized layer and isolated from trench sidewalls by a second dielectric layer. The oxidation step can be enhanced by either chemically or physically altering the top portion polysilicon such as by implanting impurities.

Methods of forming inter-poly dielectric (IPD) layers in power semiconductor devices

A method of manufacturing a semiconductor device having a charge control trench and an active control trench with a thick oxide bottom includes forming a drift region, a well region extending above the drift region, an active trench extending through the well region and into the drift region, a charge control trench extending deeper into the drift region than the active trench, an oxide film that fills the active trench, the charge control trench and covers a top surface of the substrate, an electrode in the active trench, and source regions. The method also includes etching the oxide film off the top surface of the substrate and inside the active trench to leave a substantially flat layer of thick oxide having a target thickness at the bottom of the active trench.

Methods of making power semiconductor devices with thick bottom oxide layer

A method of forming a semiconductor device includes the following. Removing portions of a silicon layer such that a trench having sidewalls which fan out near the top of the trench to extend directly over a portion of the silicon layer is formed in the silicon layer; and forming source regions in the silicon layer adjacent the trench sidewall such that the source regions extend into the portions of the silicon layer directly over which the trench sidewalls extend.

Power device with trenches having wider upper portion than lower portion

A method of forming a semiconductor device includes the following. A masking layer with opening is formed over a silicon layer. The silicon layer is isotropically etched through the masking layer openings so as to remove bowl-shaped portions of the silicon layer, each of which includes a middle portion and outer portions extending directly underneath the masking layer. The outer portions form outer sections of corresponding trenches. Additional portions of the silicon layer are removed through the masking layer openings so as to form a middle section of the trenches which extends deeper into the silicon layer than the outer sections of the trenches. A first doped region of a first conductivity type is formed in an upper portion of the silicon layer. An insulating layer is formed within each trench, and extends directly over a portion of the first doped region adjacent each trench sidewall. Silicon is removed from adjacent each trench until, of the first doped region, only the portions adjacent the trench sidewalls remain. The remaining portions of the first doped region adjacent the trench sidewalls form source regions which are self-aligned to the trenches.

A field effect transistor includes a plurality of trenches extending into a silicon layer. Each trench has upper sidewalls that fan out. Contact openings extend into the silicon layer between adjacent trenches such that each trench and an adjacent contact opening form a common upper sidewall portion. Body regions extend between adjacent trenches, and source regions extend in the body regions adjacent opposing sidewalls of each trench. The source regions have a conductivity type opposite that of the body regions.

A semiconductor device is formed as follows. A plurality of trenches is formed in a silicon layer. An insulating layer filling an upper portion of each trench is formed. Exposed silicon is removed from adjacent the trenches to expose an edge of the insulating layer in each trench, such that the exposed edge of the insulating layer in each trench defines a portion of each contact opening formed between every two adjacent trenches.

Method for forming a trench MOSFET having self-aligned features

Self-aligned trench MOSFETs and methods for manufacturing the same are disclosed. By having a self-aligned structure, the number of MOSFETS per unit area&#x2014;the cell density&#x2014;is increased, making the MOSFETs cheaper to produce. The self-aligned structure for the MOSFET is provided by making the sidewall of the overlying isolation dielectric layer substantially aligned with the sidewall of the gate conductor. Such an alignment can be made through any number of methods such as using a dual dielectric process, using a selective dielectric oxidation process, using a selective dielectric deposition process, or a spin-on-glass dielectric process.

Self-aligned trench MOSFETs and methods for making the same

In accordance with an embodiment of the present invention, a semiconductor device is formed as follows. An exposed surface area of a silicon layer where silicon can be removed is defined. A portion of the silicon layer is removed to form a middle section of a trench extending into the silicon layer from the exposed surface area of the silicon layer. Additional exposed surface areas of the silicon layer where silicon can be removed are defined. Additional portions of the silicon layer are removed to form outer sections of the trench such that the outer sections of the trench extend into the silicon layer from the additional exposed surface areas of the silicon layer. The middle section of the trench extends deeper into the silicon layer than the outer sections of the trench.

Structure and method for forming a trench MOSFET having self-aligned features

A method for removing contaminants on a semiconductor substrate is disclosed. In one embodiment, the method includes forming a dielectric structure on the semiconductor substrate. A portion of an electrically conducting region to a side of the dielectric structure is etched, and a conductive material is deposited on the etched electrically conducting region.

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Cedar Hills, UT, United States of America

Becky Losee