US 12,764,984 B2Granted

Semiconductor device with field plate and multiple-part gate structure and method of fabrication therefor

AssigneeNXP USA, Inc.

InventorsJie Hu, Bernhard Grote

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Abstract

A semiconductor device includes a semiconductor substrate, source and drain electrodes, lower dielectric layer(s) disposed over an upper surface of the semiconductor substrate, and intermediate dielectric layer(s) disposed over the lower dielectric layer(s). The device also includes a multiple-part gate structure with lower and upper gate electrodes. The lower gate electrode is formed from a first portion of a first conductive layer. The upper gate electrode is formed from a second conductive layer. The device further includes a lower field plate disposed between the lower gate electrode and the drain electrode. The lower field plate is formed from a second portion of the first conductive layer. Methods of forming the semiconductor device enable the lower gate electrode and the lower field plate to be created in a self-aligned manner.

Claims14

Dependent claims

A metal-insulator-semiconductor field effect transistor (MISFET) device-comprising:

a semiconductor substrate comprising an upper surface and a channel;
a source electrode overlying the semiconductor substrate;
a drain electrode overlying the semiconductor substrate;
one or more lower dielectric layers disposed over the upper surface of the semiconductor substrate;
one or more intermediate dielectric layers disposed over the one or more lower dielectric layers;
a multiple-part gate structure that includes
a lower gate electrode formed from a first portion of a first conductive layer, wherein the first portion of the first conductive layer includes a first segment that extends through a first gate opening in the one or more lower dielectric layers over the channel, and a second segment that overlies the one or more lower dielectric layers and extends from the first gate opening toward the drain electrode, and
an upper gate electrode formed from a second conductive layer, wherein the upper gate electrode extends through the one or more intermediate dielectric layers and contacts the lower gate electrode;
a gate dielectric between the first segment of the lower gate electrode and the semiconductor substrate;
and
a lower field plate disposed between the lower gate electrode and the drain electrode, wherein the lower field plate is formed from a second portion of the first conductive layer.

8 more elements

A method for forming a semiconductor device, the method comprising:

forming one or more lower dielectric layers over an upper surface of a semiconductor substrate that includes a channel;
forming source and drain electrodes over the upper surface of the semiconductor substrate;
forming a first gate opening through the one or more lower dielectric layers between the source and drain contacts, wherein the first gate opening extends toward the upper surface of the semiconductor substrate;
simultaneously forming a lower gate electrode and a lower field plate from a first conductive layer, wherein the lower gate electrode includes a first segment that extends into the first gate opening, and a second segment that overlies the one or more lower dielectric layers and extends from the first gate opening toward the drain electrode, and wherein the lower field plate is disposed between the lower gate electrode and the drain electrode and overlies the one or more lower dielectric layers;
forming one or more intermediate dielectric layers over the one or more lower dielectric layers;
forming a second gate opening through the one or more intermediate dielectric layers to expose the lower gate electrode;
and
forming an upper gate electrode on and over the lower gate electrode.

5 more elements

Dependencies are inferred from the claim text.