Maxim Integrated Products, Inc.

Volterra Semiconductor Corporation

Badredin Fatemizadeh

Marco A Zuniga

John Xia

Amit Paul

Yang Lu

Jun Ruan

Jayasimha Prasad

Vijay Parthasarathy

Adam Brand

Rajwinder Singh

Tom K Castro

Chi-Nung Ni

Vipindas Pala

Chiteh Chiang

Craig Cassella

Min Xu

Marco A Zungia

A lateral double-diffused metal-oxide-semiconductor transistor includes a silicon semiconductor structure and a vertical gate. The vertical gate include a (a) gate conductor extending from a first outer surface of the silicon semiconductor structure into the silicon semiconductor structure and (b) a gate dielectric layer including a least three dielectric sections. Each of the at least three dielectric sections separates the gate conductor from the silicon semiconductor structure by a respective separation distance, where each of the respective separation distances is different from each other of the respective separation distances.

LDMOS transistors including vertical gates with multiple dielectric sections, and associated methods

A multi-transistor device includes first and second lateral double-diffused metal-oxide-semiconductor field effect (LDMOS) transistors sharing a first p-type reduced surface field (RESURF) layer and a first drain n+ region. In certain embodiments, the first LDMOS transistor includes a first drift region, the second LDMOS transistor includes a second drift region, and the first and second drift regions are at least partially separated by the first p-type RESURF layer in a thickness direction.

Multi-transistor device including first and second LDMOS transistors having respective drift regions separated in a thickness direction by a shared RESURF layer

A lateral double-diffused metal-oxide-semiconductor field effect (LDMOS) transistor includes a silicon semiconductor structure, a dielectric layer at least partially disposed in a trench of the silicon semiconductor structure in a thickness direction, and a gate conductor embedded in the dielectric layer and extending into the trench in the thickness direction. The dielectric layer and the gate conductor are at least substantially symmetric with respect to a center axis of the trench extending in the thickness direction, as seen when the LDMOS transistor is viewed cross-sectionally in a direction orthogonal to the lateral and thickness directions.

LDMOS transistors and associated systems and methods

A lateral double-diffused metal-oxide-semiconductor (LDMOS) transistor includes a silicon semiconductor structure and a vertical gate. The vertical gate includes (a) a first gate conductor and a second gate conductor each extending from a first outer surface of the silicon semiconductor structure into the silicon semiconductor structure in a thickness direction, (b) a first separation dielectric layer separating the first gate conductor from the second gate conductor within the vertical gate, and (c) a gate dielectric layer separating each of the first gate conductor and the second gate conductor from the silicon semiconductor structure.

Transistors with dual gate conductors, and associated methods

A dual-gate, self-aligned lateral double-diffused metal-oxide-semiconductor (LDMOS) transistor includes a silicon semiconductor structure, a lateral gate including a first dielectric layer and a first conductive layer stacked on the silicon semiconductor structure in a thickness direction, and a vertical gate. The vertical gate includes a second dielectric layer and a second conductive layer disposed in a trench of the silicon semiconductor structure, the second dielectric layer defining an edge of the lateral gate in a lateral direction. A method for forming a dual-gate, self-aligned LDMOS transistor includes (a) forming a vertical gate of the LDMOS transistor in a trench of a silicon semiconductor structure and (b) defining a lateral edge of a lateral gate of the LDMOS transistor using the vertical gate.

Self-aligned, dual-gate LDMOS transistors and associated methods

A voltage regulator includes a high-side device, a low-side device, and a controller. The high-side device includes first and second transistors each coupled between an input terminal and an intermediate terminal, where the first transistor has a higher breakdown voltage than the second transistor. The low-side device is coupled between the intermediate terminal and a ground terminal. The controller is configured to drive the high-side and low-side devices to (a) alternately couple the intermediate terminal to the input terminal and the ground terminal and (b) cause the first transistor to control a voltage across the second transistor during switching transitions of the second transistor.

Voltage regulators with multiple transistors

A lateral double-diffused metal-oxide-semiconductor field effect transistor includes a silicon semiconductor structure, first and second gate structures, and a trench dielectric layer. The first and second gate structures are disposed on the silicon semiconductor structure and separated from each other in a lateral direction. The trench dielectric layer is disposed in a trench in the silicon semiconductor structure and extends at least partially under each of the first and second gate structures in a thickness direction orthogonal to the lateral direction.

A lateral double-diffused metal-oxide-semiconductor field effect (LDMOS) transistor includes a silicon semiconductor structure including (a) a base layer, (b) a p-type reduced surface field effect (RESURF) layer disposed over the base layer in a thickness direction, (c) a p-body disposed over the p-type RESURF layer in the thickness direction, (d) a source p+ region and a source n+ region each disposed in the p-body, (e) a high-voltage n-type laterally-diffused drain (HVNLDD) disposed adjacent to the p-body in a lateral direction orthogonal to the thickness direction, the HVNLDD contacting the p-type RESURF layer, and (f) a drain n+ region disposed in the HVNLDD. The LDMOS transistor further includes (a) a first dielectric layer disposed on the silicon semiconductor structure in the thickness direction over at least part of the p-body and the HVNLDD and (b) a first gate conductor disposed on the first dielectric layer in the thickness direction.

LDMOS transistors including resurf layers and stepped-gates, and associated systems and methods

The present application features a transistor that includes an n-well region implanted into a surface of a substrate, a gate region, and a source region, and a drain region. The source region is on a first side of the gate region and includes a p-body region in the n-well region. An n+ region and a p+ region are implanted in the p-body region such that the p+ region is below the n+ region. The drain region is on a second side of the gate region and includes an n+ region.

Transistor with buried P+ and source contact

A voltage regulator has an input terminal and a ground terminal. The voltage regulator includes a high-side device, a low side device, and a controller. The high-side device is coupled between the input terminal and an intermediate terminal. The high-side device includes first and second transistors each coupled between the input terminal and the intermediate terminal, such that the first transistor controls a drain-source switching voltage of the second transistor. The low-side device is coupled between the intermediate terminal and the ground terminal. The controller drives the high-side and low-side devices to alternately couple the intermediate terminal to the input terminal and the ground terminal.

Described here are transistors and fabrication methods thereof. In one implementation, a transistor includes an n-well region implanted into a surface of a substrate, and a trench in the n-well region. The trench extends from the surface to a first depth. The trench includes a gate of conductive material in the trench, and dielectric material filling a volume of the trench not filled by the conductive material. The transistor also includes a p-type material in a first region extending from a second depth to a third depth, the second depth and the third depth being greater than the first depth. The transistor further includes a source region and a drain region.

Vertical gate LDMOS device

A method of fabricating a vertical gate region in LDMOS transistor includes depositing a first masking layer on an n-well region implanted on a substrate, patterning the first masking layer to define an area, depositing a second masking layer over the area, etching through the second masking layer in a first portion of the area to expose the n-well region, and etching the exposed n-well region to form a first trench. The first trench, extending from a surface of the n-well region to a first depth, is filled with an oxide. The second masking layer is etched through in a second portion of the area to expose the n-well region. A second trench is formed in the n-well, the second trench extending from the surface to a second depth, less than the first depth. An asymmetric vertical gate is formed by filling the second trench with a conductive material.

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Palo Alto, CA, United States of America

Badredin Fatemizadeh