This work demonstrates the advantage of carrying out silicon ion (Si+) implantation at high temperatures for forming controlled heavily doped regions in gallium oxide. Room temperature (RT, 25 °C) and high temperature (HT, 600 °C) Si implants were carried out into MBE grown (010) β-Ga2O3films to form ∼350 nm deep Si-doped layers with average concentrations up to ∼1.2 × 1020cm−3. For such high concentrations, the RT sample was too resistive for measurement, but the HT samples had 82.1% Si dopant activation efficiency with a high sheet electron concentration of 3.3 × 1015 cm−2and an excellent mobility of 92.8 cm2/V·s at room temperature. X-ray diffraction measurements indicate that HT implantation prevents the formation of other Ga2O3phases and results in reduced structural defects and lattice damage. These results are highly encouraging for achieving ultra-low resistance heavily doped Ga2O3layers using ion implantation.
This content will become publicly available on April 14, 2023
- Publication Date:
- NSF-PAR ID:
- Journal Name:
- Journal of Applied Physics
- Page Range or eLocation-ID:
- Sponsoring Org:
- National Science Foundation
More Like this
In situ MOCVD growth and band offsets of Al 2 O 3 dielectric on β-Ga 2 O 3 and β-(Al x Ga 1−x ) 2 O 3 thin filmsThe in situ metalorganic chemical vapor deposition (MOCVD) growth of Al 2 O 3 dielectrics on β-Ga 2 O 3 and β-(Al x Ga 1−x ) 2 O 3 films is investigated as a function of crystal orientations and Al compositions of β-(Al x Ga 1−x ) 2 O 3 films. The interface and film qualities of Al 2 O 3 dielectrics are evaluated by high-resolution x-ray diffraction and scanning transmission electron microscopy imaging, which indicate the growth of high-quality amorphous Al 2 O 3 dielectrics with abrupt interfaces on (010), (100), and [Formula: see text] oriented β-(Al x Ga 1−x ) 2 O 3 films. The surface stoichiometries of Al 2 O 3 deposited on all orientations of β-(Al x Ga 1−x ) 2 O 3 are found to be well maintained with a bandgap energy of 6.91 eV as evaluated by high-resolution x-ray photoelectron spectroscopy, which is consistent with the atomic layer deposited (ALD) Al 2 O 3 dielectrics. The evolution of band offsets at both in situ MOCVD and ex situ ALD deposited Al 2 O 3 /β-(Al x Ga 1−x ) 2 O 3 is determined as a function of Al composition, indicating the influence of themore »
The role of third cation doping on phase stability, carrier transport and carrier suppression in amorphous oxide semiconductorsAmorphous oxide semiconductors (AOSs), specifically those based on ternary cation systems such as Ga-, Si-, and Hf-doped InZnO, have emerged as promising material candidates for application in next-gen transparent electronic and optoelectronic devices. Third cation-doping is a common method used during the manufacturing of amorphous oxide thin film transistors (TFTs), primarily with the intention of suppressing carrier generation during the fabrication of the channel layer of a transistor. However, the incorporation of a third cation species has been observed to negatively affect the carrier transport properties of the thin film, as it may act as an additional scattering center and subsequently lower the carrier mobility from ∼20–40 cm 2 V −1 s −1 of In 2 O 3 or a binary cation system ( i.e. , InZnO) to ∼1–10 cm 2 V −1 s −1 . This study investigates the structural, electrical, optoelectronic, and chemical properties of the ternary cation material system, InAlZnO (IAZO). The optimized carrier mobility (Hall Effect) of Al-doped InZnO is shown to remain as high as ∼25–45 cm 2 V −1 s −1 . Furthermore, Al incorporation in InZnO proves to enhance the amorphous phase stability under thermal stresses when compared to baseline InZnO films. Thinmore »
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.
NiO/β-(Al x Ga 1−x ) 2 O 3 /Ga 2 O 3 heterojunction lateral rectifiers with reverse breakdown voltage >7 kVNiO/β-(Al x Ga 1− x ) 2 O 3 /Ga 2 O 3 heterojunction lateral geometry rectifiers with diameter 50–100 μm exhibited maximum reverse breakdown voltages >7 kV, showing the advantage of increasing the bandgap using the β-(Al x Ga 1− x ) 2 O 3 alloy. This Si-doped alloy layer was grown by metal organic chemical vapor deposition with an Al composition of ∼21%. On-state resistances were in the range of 50–2180 Ω cm 2 , leading to power figures-of-merit up to 0.72 MW cm −2 . The forward turn-on voltage was in the range of 2.3–2.5 V, with maximum on/off ratios >700 when switching from 5 V forward to reverse biases up to −100 V. Transmission line measurements showed the specific contact resistance was 0.12 Ω cm 2 . The breakdown voltage is among the highest reported for any lateral geometry Ga 2 O 3 -based rectifier.