# US 10,374,068 B2 · Tunnel field effect transistors

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- Number: US 10,374,068 B2
- Document ID: US10374068B2
- Status: Granted
- Kind: B2
- Application number: 15/403,998
- Filed: 2017-01-11
- Published: 2017-05-04
- Granted: 2019-08-06
- Earliest claimed: 2009-12-17
- Assignees: Infineon Technologies AG; Indian Institute of Technology Bombay
- Applicants: Infineon Technologies AG; Indian Institute of Technology Bombay
- Inventors: Harald Gossner; Ramgopal Rao; Ram Asra
- Web page: https://patentgrep.com/patent/US10374068B2

## CPC

- H10D 48/383: {Quantum effect devices, e.g. of devices using quantum reflection, diffraction or interference effects}
- H10D 8/70: Tunnel-effect diodes
- H10D 12/021: {of gated diodes, e.g. field-controlled diodes [FCD]}
- H10D 12/211: {Gated diodes}
- H10D 30/031: {of thin-film transistors [TFT]}
- H10D 30/6715: {characterised by the doping profiles, e.g. having lightly-doped source or drain extensions}
- H10D 30/6757: {characterised by the structure of the channel, e.g. transverse or longitudinal shape or doping profile (TFTs having channel structures for preventing kink or snapback effects H10D30/6708; TFTs having lightly-doped source or drain extensions H10D30/6715)}
- H10D 30/6758: {characterised by the insulating substrates}
- H10D 62/165: {Tunnel injectors}
- H10D 62/126: {Top-view geometrical layouts of the regions or the junctions}
- H10D 62/822: comprising only Group IV materials heterojunctions, e.g. Si/Ge heterojunctions
- H10P 30/204: {into Group IV semiconductors}
- H10P 30/208: {of electrically inactive species}
- H10P 30/222: {characterised by the angle between the ion beam and the crystal planes or the main crystal surface (characterised by the angle between the ion beam and the mask H10P30/221)}
- H10P 30/225: {of a molecular ion, e.g. decaborane}
- H10D: INORGANIC ELECTRIC SEMICONDUCTOR DEVICES
- H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10

## Abstract

Tunnel field effect devices and methods of fabricating tunnel field effect devices are described. In one embodiment, the semiconductor device includes a first drain region of a first conductivity type disposed in a first region of a substrate, a first source region of a second conductivity type disposed in the substrate, the second conductivity type being opposite the first conductivity type, a first channel region electrically coupled between the first source region and the first drain region, the first source region underlying a least a portion of the first channel region, and a first gate stack overlying the first channel region.

## Claims

### Claim 1

A semiconductor device comprising:
a first drain region of a first conductivity type disposed in a first region of a substrate;
a first source region of a second conductivity type disposed in said substrate, said second conductivity type being opposite said first conductivity type;
a first channel region of the first conductivity type electrically coupled between said first source region and said first drain region;
a first gate stack overlying said first channel region;
a first doped region of the first conductivity type disposed between the first source region and the first drain region, wherein the first doped region is doped to a lower doping than the first source region, and wherein at least a portion of the first doped region is in direct contact with a bottom surface of the first channel region; and
a second doped region of the second conductivity type disposed between the first source region and the first drain region, wherein the second doped region is doped to a higher doping than the first doped region, wherein at least a portion of the second doped region is in direct contact with the bottom surface of the first channel region, and
wherein a tunnel junction is formed at the intersection between the first source region and the first channel region, wherein the first channel region has a lower dopant concentration than a dopant concentration of the first source region so that, at the tunnel junction between the first source region and the first channel region, a net doping concentration varies abruptly from the first source region to the first channel region.

### Claim 2 (depends on 1)

The device of claim 1, wherein the first channel region comprises germanium, wherein the germanium content is at least 15% by concentration.

### Claim 3 (depends on 1)

The device of claim 1, wherein the second doped region comprises a crystal orientation that enhances a tunnel current between the first channel region and the second doped region, wherein the crystal orientation of the second doped region is different than a crystal orientation within the substrate, wherein the substrate comprises a bulk substrate.

### Claim 4 (depends on 1)

The device of claim 1, further comprising:
a second drain region of the second conductivity type disposed in a second region of the substrate;
a second source region of the first conductivity type disposed in said substrate;
a second channel region electrically coupled between said second source region and said second drain region; and
a second gate stack overlying said second channel region.

### Claim 5 (depends on 1)

The device of claim 1, wherein the net doping concentration is less than the lower dopant concentration.