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Vertical-type two-dimensional hole gas diamond metal oxide semiconductor field-effect transistors
Nobutaka Oi1, Masafumi Inaba1,2,3, Satoshi Okubo1
1Faculty of Science and Engineering, Waseda University, 3-4-1, Ohkubo, Shinjuku-ku, Tokyo, 169-8555, Japan.
Scientific Reports
|July 15, 2018
Summary
Researchers developed vertical p-channel diamond Metal-Oxide-Semiconductor Field-Effect Transistors (MOSFETs) with trench structures. These devices achieve high current densities and on/off ratios, advancing power semiconductor technology.
Area of Science:
- Materials Science
- Electrical Engineering
- Semiconductor Physics
Background:
- Power semiconductor devices need both low on-resistivity and high breakdown voltages.
- Vertical-type Metal-Oxide-Semiconductor Field-Effect Transistors (MOSFETs) are promising but incomplete in diamond technology.
- Complementary circuits require both n-channel and p-channel devices with comparable performance.
Purpose of the Study:
- To demonstrate vertical-type p-channel diamond MOSFETs with trench structures.
- To achieve drain current densities comparable to n-channel wide bandgap devices for complementary inverters.
- To investigate the use of two-dimensional hole gases for device channels and drift layers.
Main Methods:
- Fabrication of vertical-type p-channel diamond MOSFETs utilizing trench structures.
- Induction of two-dimensional hole gases using atomic layer deposited Al2O3 for channel and drift layers.
- Implementation of a p+ substrate as the drain and a planar surface for source and gate, with drift layer on sidewalls.
- Formation of a nitrogen-doped n-type blocking layer via ion implantation and epitaxial growth.
Main Results:
- Demonstrated vertical-type p-channel diamond MOSFETs with performance comparable to n-channel wide bandgap devices.
- Achieved maximum drain current densities exceeding 200 mA/mm at a 12 µm source-drain distance.
- Obtained on/off ratios greater than eight orders of magnitude.
- Confirmed drain current reaching the lower measurement limit in the off-state at room temperature.
Conclusions:
- Successfully developed high-performance vertical p-channel diamond MOSFETs suitable for complementary circuits.
- The use of two-dimensional hole gases and trench structures enables competitive current densities and excellent on/off ratios.
- These findings represent a significant advancement in diamond-based power semiconductor technology.
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