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1. Rapid Inverse Design of GaN-on-GaN Diode with Guard Ring Termination for BV and (V F Q) −1 Co-Optimization

   https://doi.org/10.1109/ISPSD57135.2023.10147511  

   Yee, Nathan ; Lu, Albert ; Wang, Yifan ; Porter, Matthew ; Zhang, Yuhao ; Wong, Hiu Yung ( May 2023 , 2023 35th International Symposium on Power Semiconductor Devices and ICs (ISPSD))

   GaN-on-GaN vertical diode is a promising device for next-generation power electronics. Its breakdown voltage (BV) is limited by edge termination designs such as guard rings. The design space of guard rings is huge and it is difficult to optimize manually. In this paper, we propose an effective inverse design strategy to co-optimize BV and (V F Q) −1 , where BV, V F , and Q are the breakdown voltage, forward voltage, and reserve capacitive charge of the diode, respectively. Using rapid Technology Computer-Aided-Design (TCAD) simulations, neural network (NN), and Pareto front generation, a GaN-on-GaN diode is optimized within 24 hours. We can obtain structures with 200V higher BV at medium (V F Q) −1 or find a nearly ideal BV structure with 25% higher BV 2 /R on compared to the best randomly generated TCAD data. 

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2. Recombination Rates of In x Ga 1−x N/Al y Ga 1−y N/GaN Multiple Quantum Wells Emitting From 640 to 565 nm

   https://doi.org/10.1109/JQE.2021.3111402  

   Muyeed, Syed Ahmed ; Borovac, Damir ; Xue, Haotian ; Wei, Xiongliang ; Song, Renbo ; Tansu, Nelson ; Wierer, Jonathan J. ( December 2021 , IEEE Journal of Quantum Electronics)
3. Magnetic properties of MBE grown Mn 4 N on MgO, SiC, GaN and Al 2 O 3 substrates

   https://doi.org/10.1063/1.5130485  

   Zhang, Zexuan ; Cho, Yongjin ; Singhal, Jashan ; Li, Xiang ; Dang, Phillip ; Lee, Hyunjea ; Casamento, Joseph ; Tang, Yongjian ; Xing, Huili Grace ; Jena, Debdeep ( January 2020 , AIP Advances)
4. Epitaxial Sc x Al 1− x N on GaN exhibits attractive high-K dielectric properties

   https://doi.org/10.1063/5.0075636  

   Casamento, Joseph ; Lee, Hyunjea ; Maeda, Takuya ; Gund, Ved ; Nomoto, Kazuki ; van Deurzen, Len ; Turner, Wesley ; Fay, Patrick ; Mu, Sai ; Van de Walle, Chris G. ; et al ( April 2022 , Applied Physics Letters)

   Epitaxial Sc_xAl_1−xN thin films of ∼100 nm thickness grown on metal polar GaN substrates are found to exhibit significantly enhanced relative dielectric permittivity (ε_r) values relative to AlN. ε_rvalues of ∼17–21 for Sc mole fractions of 17%–25% ( x = 0.17–0.25) measured electrically by capacitance–voltage measurements indicate that Sc_xAl_1−xN has the largest relative dielectric permittivity of any existing nitride material. Since epitaxial Sc_xAl_1−xN layers deposited on GaN also exhibit large polarization discontinuity, the heterojunction can exploit the in situ high-K dielectric property to extend transistor operation for power electronics and high-speed microwave applications.

    

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5. Anisotropic-strain-enhanced hole mobility in GaN by lattice matching to ZnGeN 2 and MgSiN 2

   https://doi.org/10.1063/5.0092709  

   Leveillee, Joshua ; Poncé, Samuel ; Adamski, Nicholas L. ; Van de Walle, Chris G. ; Giustino, Feliciano ( May 2022 , Applied Physics Letters)

   The key obstacle toward realizing integrated gallium nitride (GaN) electronics is its low hole mobility. Here, we explore the possibility of improving the hole mobility of GaN via epitaxial matching to II–IV nitride materials that have recently become available, namely, ZnGeN 2 and MgSiN 2 . We perform state-of-the-art calculations of the hole mobility of GaN using the ab initio Boltzmann transport equation. We show that effective uniaxial compressive strain of GaN along the [Formula: see text] by lattice matching to ZnGeN 2 and MgSiN 2 results in the inversion of the heavy hole band and split-off hole band, thereby lowering the effective hole mass in the compression direction. We find that lattice matching to ZnGeN 2 and MgSiN 2 induces an increase in the room-temperature hole mobility by 50% and 260% as compared to unstrained GaN, respectively. Examining the trends as a function of strain, we find that the variation in mobility is highly nonlinear; lattice matching to a hypothetical solid solution of Zn 0.75 Ge 0.75 Mg 0.25 Si 0.25 N 2 would already increase the hole mobility by 160%. 

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