TY - GEN
T1 - Electronic structure and carrier transport analysis in β-Ga 2 O 3 using a two-valley ensemble monte carlo framework
AU - Zhang, Zi Chang
AU - Wu, Ye
AU - Lu, Chao
AU - Ahmed, Shaikh S.
N1 - Publisher Copyright:
© 2018 IEEE.
PY - 2019/1/8
Y1 - 2019/1/8
N2 - We carry out two-valley ensemble Monte Carlo (EMC) simulations for the calculation of electron mobility in β-Ga 2 O 3 . First, the electronic bandstructure is determined using first-principles density function theory (DFT) as available in the open-source Quantum Espresso package. A Perdew-Zunger LDA exchange-correlation function generated ultrasoft pseudopotential was used in the calculations. The following electron scattering mechanisms are found to be important: Acoustic deformation potential, ionized impurity, and polar optical phonons (POP). In β-Ga 2 O 3 , low crystal symmetry induces multiple phonon modes, which complicates the mobility calculation. Here, 50 meV of POP energy was found to be good enough for the Fröhlich scattering model. For low electrical fields at 300K, we report an electron mobility of 113 cm 2 /V·s. Also, in the range of 150K-500K, our simulation results match very well with reported Hall mobility data. For high electrical fields, β-Ga 2 O 3 displays a negative differential mobility (NDM). Critical electrical field is found to be 250 KV/cm with a maximum steady-state drift velocity of 2.2×10 5 m/s. Finally, for a realistic device with an Al 2 O 3 /β-Ga 2 O 3 interface, the influence of surface roughness scattering (SRS) was studied via Ando's model. Results show that electron mobility in β-Ga 2 O 3 dramatically decreases with the inclusion of SRS.
AB - We carry out two-valley ensemble Monte Carlo (EMC) simulations for the calculation of electron mobility in β-Ga 2 O 3 . First, the electronic bandstructure is determined using first-principles density function theory (DFT) as available in the open-source Quantum Espresso package. A Perdew-Zunger LDA exchange-correlation function generated ultrasoft pseudopotential was used in the calculations. The following electron scattering mechanisms are found to be important: Acoustic deformation potential, ionized impurity, and polar optical phonons (POP). In β-Ga 2 O 3 , low crystal symmetry induces multiple phonon modes, which complicates the mobility calculation. Here, 50 meV of POP energy was found to be good enough for the Fröhlich scattering model. For low electrical fields at 300K, we report an electron mobility of 113 cm 2 /V·s. Also, in the range of 150K-500K, our simulation results match very well with reported Hall mobility data. For high electrical fields, β-Ga 2 O 3 displays a negative differential mobility (NDM). Critical electrical field is found to be 250 KV/cm with a maximum steady-state drift velocity of 2.2×10 5 m/s. Finally, for a realistic device with an Al 2 O 3 /β-Ga 2 O 3 interface, the influence of surface roughness scattering (SRS) was studied via Ando's model. Results show that electron mobility in β-Ga 2 O 3 dramatically decreases with the inclusion of SRS.
KW - Ensemble Monte Carlo
KW - Ga O
KW - mobility
KW - surface roughness scattering
UR - http://www.scopus.com/inward/record.url?scp=85061821735&partnerID=8YFLogxK
U2 - 10.1109/NMDC.2018.8605830
DO - 10.1109/NMDC.2018.8605830
M3 - Conference Proceeding
AN - SCOPUS:85061821735
T3 - 2018 IEEE 13th Nanotechnology Materials and Devices Conference, NMDC 2018
BT - 2018 IEEE 13th Nanotechnology Materials and Devices Conference, NMDC 2018
PB - Institute of Electrical and Electronics Engineers Inc.
T2 - 13th IEEE Nanotechnology Materials and Devices Conference, NMDC 2018
Y2 - 14 October 2018 through 17 October 2018
ER -