Ga 2 O 3 Based Heterostructure FETs (HFETs) for Microwave …
217
Fig. 5 Low-field electron mobility in β-Ga 2 O 3 over varying temperature, mobility value ~125
cm 2 /Vs at 300 K, green (filled) circles are measured values from Ref. [50], and blue outline (unfilled)
symbols are calculated values from Ref. [51]
Fig. 6 Transient characteristics of drift velocity under increasing electric fields from 50 to 450
kV/cm, drift velocity under low-field (upto 150 kV/cm) monotonically reaches a steady-state value,
adopted from Ref. [52]
μ n (E) =
μ n0 +
vsat
E
E
ecritn
γ
1 +
E
ecritn
γ
(1)
where low-field mobility μ n0 = 140 cm
2 /Vs, critical field for electrons ecritn = 2.25
× 10
5 V/cm, and γ = 2.84 are user-defined values for β-Ga 2 O 3 velocity-field curves
fitting parameters [52] which are used to replace standard values of the NDC model
[57] before the simulation.
Although bulk mobility in β-Ga 2 O 3 crystals limited to 200 cm
2 /Vs, heterojunctions can offer higher impurity controlled mobility by spatially isolating electrons
from dopants. The high-electron mobility up to ~400 cm
2 /Vs in two-dimensional
217
Fig. 5 Low-field electron mobility in β-Ga 2 O 3 over varying temperature, mobility value ~125
cm 2 /Vs at 300 K, green (filled) circles are measured values from Ref. [50], and blue outline (unfilled)
symbols are calculated values from Ref. [51]
Fig. 6 Transient characteristics of drift velocity under increasing electric fields from 50 to 450
kV/cm, drift velocity under low-field (upto 150 kV/cm) monotonically reaches a steady-state value,
adopted from Ref. [52]
μ n (E) =
μ n0 +
vsat
E
E
ecritn
γ
1 +
E
ecritn
γ
(1)
where low-field mobility μ n0 = 140 cm
2 /Vs, critical field for electrons ecritn = 2.25
× 10
5 V/cm, and γ = 2.84 are user-defined values for β-Ga 2 O 3 velocity-field curves
fitting parameters [52] which are used to replace standard values of the NDC model
[57] before the simulation.
Although bulk mobility in β-Ga 2 O 3 crystals limited to 200 cm
2 /Vs, heterojunctions can offer higher impurity controlled mobility by spatially isolating electrons
from dopants. The high-electron mobility up to ~400 cm
2 /Vs in two-dimensional