High Band-to-Band Tunneling Current in InAs/GaSb Heterojunction Esaki Diodes by the Enhancement of Electric Fields Close to the Mesa Sidewalls
Journal
IEEE Transactions on Electron Devices
Journal Volume
68
Journal Issue
8
Pages
3748-3754
Date Issued
2021
Author(s)
Abstract
InAs/GaSb heterojunction Esaki diodes with a high peak current density of 9 MA/cm2 are demonstrated. Negative differential resistance (NDR) is achieved from 300 to 4 K, showing that band-to-band tunneling (BTBT) is the dominant transport mechanism. By increasing the doping concentrations, the peak current increases because of more carriers available for tunneling. NDR is also clearly observed for the devices with nondegenerate doping concentrations, which could be attributed to the induced quantum wells at the InAs/GaSb heterojunction. To calibrate the BTBT current, devices of different mesa areas were characterized. The peak current density increases as the device is scaled down. A model of tunneling enhancement close to the mesa sidewalls by the surface defects is proposed. TCAD simulations show that the electric fields close to the sidewalls are enhanced because of the induced surface defects by dry etching in InAs and GaSb. Careful processing steps to reduce those surface defects during etching steps are required to avoid an overestimation of the BTBT current. ? 1963-2012 IEEE.
Subjects
Band-to-band tunneling (BTBT)
Esaki diode
InAs/GaSb
quantum confinement
Dry etching
Electric fields
Heterojunctions
III-V semiconductors
Indium antimonides
Indium arsenide
Semiconducting antimony compounds
Surface defects
Tunnel diodes
Band to band tunneling
Doping concentration
High-peak currents
Negative differential resistances
Peak current density
Processing steps
TCAD simulation
Transport mechanism
Gallium compounds
Type
journal article