More Like this

1. 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 films

   https://doi.org/10.1063/5.0104433  

   Bhuiyan, A F ; Meng, Lingyu ; Huang, Hsien-Lien ; Hwang, Jinwoo ; Zhao, Hongping ( October 2022 , Journal of Applied Physics)

   The 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 »deposition method, orientation, and Al composition of β-(Al x Ga 1−x ) 2 O 3 films on resulting band alignments. Type II band alignments are determined at the MOCVD grown Al 2 O 3 /β-(Al x Ga 1−x ) 2 O 3 interfaces for the (010) and (100) orientations, whereas type I band alignments with relatively low conduction band offsets are observed along the [Formula: see text] orientation. The results from this study on MOCVD growth and band offsets of amorphous Al 2 O 3 deposited on differently oriented β-Ga 2 O 3 and β-(Al x Ga 1−x ) 2 O 3 films will potentially contribute to the design and fabrication of future high-performance β-Ga 2 O 3 and β-(Al x Ga 1−x ) 2 O 3 based transistors using MOCVD in situ deposited Al 2 O 3 as a gate dielectric.« less
2. γ -phase inclusions as common structural defects in alloyed β -(Al _x Ga _1−x ) ₂ O ₃ and doped β -Ga ₂ O ₃ films

   https://doi.org/10.1063/5.0038861  

   Chang, Celesta S. ; Tanen, Nicholas ; Protasenko, Vladimir ; Asel, Thaddeus J. ; Mou, Shin ; Xing, Huili Grace ; Jena, Debdeep ; Muller, David A. ( May 2021 , APL Materials)
3. Band offsets of (100) β -(Al _x Ga _1−x ) ₂ O ₃ / β -Ga ₂ O ₃ heterointerfaces grown via MOCVD

   https://doi.org/10.1063/5.0031584  

   Bhuiyan, A F ; Feng, Zixuan ; Johnson, Jared M. ; Huang, Hsien-Lien ; Hwang, Jinwoo ; Zhao, Hongping ( December 2020 , Applied Physics Letters)
4. Thermal Conductivity of β-Phase Ga ₂ O ₃ and (Al _x Ga _{1– x} ) ₂ O ₃ Heteroepitaxial Thin Films

   https://doi.org/10.1021/acsami.1c08506  

   Song, Yiwen ; Ranga, Praneeth ; Zhang, Yingying ; Feng, Zixuan ; Huang, Hsien-Lien ; Santia, Marco D. ; Badescu, Stefan C. ; Gonzalez-Valle, C. Ulises ; Perez, Carlos ; Ferri, Kevin ; et al ( August 2021 , ACS Applied Materials & Interfaces)
5. Temperature dependent pulsed IV and RF characterization of β -(Al _x Ga _1−x ) ₂ O ₃ /Ga ₂ O ₃ hetero-structure FET with ex situ passivation

   https://doi.org/10.1063/5.0083657  

   Saha, Chinmoy Nath ; Vaidya, Abhishek ; Singisetti, Uttam ( April 2022 , Applied Physics Letters)

   In this work, we report a study of the temperature dependent pulsed current voltage and RF characterization of [Formula: see text]-(Al x Ga 1−x ) 2 O 3 /Ga 2 O 3 hetero-structure FETs (HFETs) before and after silicon nitride (Si 3 N 4 ) passivation. Under sub-microsecond pulsing, a moderate DC-RF dispersion (current collapse) is observed before passivation in gate lag measurements, while no current collapse is observed in the drain lag measurements. The dispersion in the gate lag is possibly attributed to interface traps in the gate–drain access region. DC-RF dispersion did not show any strong dependence on the pulse widths. Temperature dependent RF measurements up to 250 °C do not show degradation in the cutoff frequencies. After Si 3 N 4 deposition at 350 °C, a shift of the threshold voltage is observed which changed the DC characteristics. However, the current collapse is eliminated; at 200 ns pulse widths, a 50% higher current is observed compared to the DC at high drain voltages. No current collapse is observed even at higher temperatures. RF performance of the passivated devices does not show degradation. These results show that ex situ deposited Si 3 N 4 is a potential candidate for passivation ofmore »[Formula: see text]-(Al x Ga 1−x ) 2 O 3 /Ga 2 O 3 HFETs.« less