# US 10,872,962 B2 · Steep-switch field effect transistor with integrated bi-stable resistive system

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- Number: US 10,872,962 B2
- Document ID: US10872962B2
- Status: Granted
- Kind: B2
- Application number: 15/894,218
- Filed: 2018-02-12
- Published: 2019-08-15
- Granted: 2020-12-22
- Earliest claimed: 2018-02-12
- Assignees: International Business Machines Corporation
- Applicants: International Business Machines Corporation
- Inventors: Julien Frougier; Nicolas Loubet; Ruilong Xie; Daniel Chanemougame; Ali Razavieh; Kangguo Cheng
- Web page: https://patentgrep.com/patent/US10872962B2

## CPC

- H10D 64/605: {Source, drain, or gate electrodes for FETs comprising highly resistive materials}
- H10D 30/62: Fin field-effect transistors [FinFET]
- H10D 84/0158: {the components including FinFETs}
- H10D 84/038: {using silicon technology, e.g. SiGe}
- H10D 84/834: {comprising FinFETs}
- H10N 99/03: {Devices using Mott metal-insulator transition, e.g. field-effect transistor-like devices}
- H10P 95/062: {involving a dielectric removal step}
- H10W 20/40: Interconnections external to wafers or substrates, e.g. back-end-of-line [BEOL] metallisations or vias connecting to gate electrodes
- H10W 20/49: Adaptable interconnections, e.g. fuses or antifuses
- H04L 67/10: in which an application is distributed across nodes in the network (software deployment G06F8/60; multiprogramming arrangements G06F9/46)
- H10D: INORGANIC ELECTRIC SEMICONDUCTOR DEVICES
- H10N: ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10
- H10W: GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10
- H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M)

## Abstract

Fabricating a steep-switch transistor includes receiving a semiconductor structure including a substrate, a fin disposed on the substrate, a plurality of source/drains disposed on the substrate adjacent to the fin, a gate disposed upon the fin, a cap disposed on the gate, and a plurality of trenches, each trench extending to a corresponding one of the plurality of source/drains. A trench contact is formed in each of the trenches in contact with the corresponding source/drain. A recess is formed in a portion of each trench contact below a top surface of the cap. A bi-stable resistive system (BRS) material is deposited in each recess in contact with the portion of the trench contact. A source/drain contact is formed upon the BRS material, a portion of the trench contact, the BRS material, and a portion of the source/drain contact forming a reversible switch for each of the corresponding source/drains.

## Claims

### Claim 1

An apparatus comprising:
a semiconductor structure including a substrate, a plurality of fins disposed on the substrate, a plurality of sources/drains disposed on the substrate, a source/drain in the plurality of sources/drains disposed adjacent to a fin in the plurality of fins, a plurality of gates wherein a gate in the plurality of gates is disposed upon the fin, a cap disposed on the gate, and a plurality of trenches etched into the cap, each trench extending to a corresponding one of the plurality of source/drains;
a trench contact formed in each of the trenches in contact with the corresponding source/drain;
a recess formed in a portion of each trench contact below a top surface of the cap;
a bi-stable resistive system (BRS) material deposited in each recess in contact with the portion of the trench contact and in contact with the cap, wherein the BRS material comprises a threshold-switching selector, and wherein an assembly is formed by monolithically integrating the BRS material on the source/drain; and
a source/drain contact formed upon the BRS material, a portion of the trench contact, the BRS material, and a portion of the source/drain contact forming a reversible switch for each of the corresponding source/drains.

### Claim 2 (depends on 1)

The apparatus of claim 1, wherein the BRS material comprises an insulator-to-metal transition (IMT) material.

### Claim 3 (depends on 2)

The apparatus of claim 2, wherein the IMT material is deposited in contact with the portion of the trench contact.

### Claim 4 (depends on 3)

The apparatus of claim 3, wherein a portion of the IMT material outside of the recess is removed using a planarization process.

### Claim 5 (depends on 4)

The apparatus of claim 4, wherein the planarization process includes a chemical mechanical planarization (CMP) process.

### Claim 6 (depends on 1)

The apparatus of claim 1, further comprising:
an oxide layer deposited within the recess, the oxide layer forming a portion of the threshold-switching selector; and
a top electrode formed within the recess upon the oxide layer.