Doping-Dependent Nonlinear Electron Mobility in GaAs|InxGa1 –xAs Coupled Quantum-Well Pseudo-Morphic MODFET Structure

• Published in: Semiconductors (Woodbury, N.Y.) Vol. 54; no. 7; pp. 788 - 795
• Main Authors: Panda, S. R., Sahu, A., Das, S., Panda, A. K., Sahu, T.
• Format: Journal Article
• Language: English
• Published: Moscow Pleiades Publishing 01-07-2020; Springer Nature B.V
• Subjects: Doping; Electron mobility; Electrons; Energy levels; Field effect transistors; Gallium arsenide; Indium gallium arsenides; Interface roughness; Low-Dimensional Systems; Magnetic Materials; Magnetism; Mathematical analysis; Occupancy; Physics; Physics and Astronomy; Quantum Phenomena; Quantum wells; Resonance scattering; Semiconductor devices; Semiconductor Structures; Substrates; Wave functions; pseudo-morphic HEMT structures; resonance of sub-band states; In; As structures nonlinear electron mobility; asymmetric double quantum wells; Ga; GaAs
• ISSN: 1063-7826; 1090-6479
• DOI: 10.1134/S1063782620070118

We analyze the asymmetric delta-doping dependence of nonlinear electron mobility μ of GaAs|In
x
Ga
1 –
x
As double quantum-well pseudo-morphic modulation doped field-effect transistor structure. We solve the Schrodinger and Poisson’s equations self-consistently to obtain the sub-band energy levels and wave functions. We consider scatterings due to the ionized impurities (IMP), alloy disorder (AL), and interface roughness (IR) to calculate μ for a system having double sub-band occupancy, in which the inter-sub-band effects play an important role. Considering the doping concentrations in the barriers towards the substrate and surface sides as
N
d
1
and
N
d
2
, respectively, we show that variation of
N
d
1
leads to a dip in μ near
N
d
1
=
N
d
2
, at which the resonance of the sub-band states occurs. A similar dip in μ as a function of
N
d
1
is also obtained at
N
d
1
=
N
d
2
by keeping (
N
d
1
+
N
d
2
) unchanged. By increasing the central barrier width and well width, the dip in μ becomes sharp. We note that even though the overall μ is governed by the IMP- and AL-scatterings, the dip in μ is mostly affected through substantial variation of the sub-band mobilities due to IR-scattering near the resonance. Our results of nonlinear electron mobility near the resonance of sub-band states can be utilized for the performance analysis of GaAs|InGaAs pseudo-morphic quantum-well field-effect transistors.