The effects of downstream plasma exposure with O 2 , N 2 or CF 4 discharges on Si-doped Ga 2 O 3 Schottky diode forward and reverse current-voltage characteristics were investigated. The samples were exposed to discharges with rf power of 50 W plasma at a pressure of 400 mTorr and a fixed treatment time of 1 min to simulate dielectric layer removal, photoresist ashing or surface cleaning steps. Schottky contacts were deposited through a shadow mask after exposure to avoid any changes to the surface. A Schottky barrier height of 1.1 eV was obtained for the reference sample without plasma treatment, with an ideality factor of 1.0. The diodes exposed to CF 4 showed a 0.25 V shift from the I–V of the reference sample due to a Schottky barrier height lowering around 14%. The diodes showed a decrease of Schottky barrier height of 2.5 and 6.5% with O 2 or N 2 treatments, respectively. The effect of plasma exposure on the ideality factor of diodes treated with these plasmas was minimal; 0.2% for O 2 and N 2 , 0.3% for CF 4 , respectively. The reverse leakage currents were 1.2, 2.2 and 4.8 μ A cm −2 for the diodes treated with O 2 , and CF 4 , and N 2 respectively. The effect of downstream plasma treatment on diode on-resistance and on-off ratio were also minimal. The changes observed are much less than caused by exposure to hydrogen-containing plasmas and indicate that downstream plasma stripping of films from Ga 2 O 3 during device processing is a relatively benign approach.
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Schottky diode characteristics on high-growth rate LPCVD β -Ga 2 O 3 films on (010) and (001) Ga 2 O 3 substrates
High crystalline quality thick β-Ga2O3drift layers are essential for multi-kV vertical power devices. Low-pressure chemical vapor deposition (LPCVD) is suitable for achieving high growth rates. This paper presents a systematic study of the Schottky barrier diodes fabricated on four different Si-doped homoepitaxial β-Ga2O3thin films grown on Sn-doped (010) and (001) β-Ga2O3substrates by LPCVD with a fast growth rate varying from 13 to 21 μm/h. A higher temperature growth results in the highest reported growth rate to date. Room temperature current density–voltage data for different Schottky diodes are presented, and diode characteristics, such as ideality factor, barrier height, specific on-resistance, and breakdown voltage are studied. Temperature dependence (25–250 °C) of the ideality factor, barrier height, and specific on-resistance is also analyzed from the J–V–T characteristics of the fabricated Schottky diodes.
more » « less- NSF-PAR ID:
- 10364165
- Publisher / Repository:
- American Institute of Physics
- Date Published:
- Journal Name:
- Applied Physics Letters
- Volume:
- 120
- Issue:
- 12
- ISSN:
- 0003-6951
- Page Range / eLocation ID:
- Article No. 122106
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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