An accurate charge control model for spontaneous and piezoelectric polarization dependent two-dimensional electron gas sheet charge density of lattice-mismatched AlGaN/GaN HEMTs

Rashmi, Rashmi; Kranti, Abhinav; Haldar, Subhasis; Gupta, R. S.

doi:10.1016/s0038-1101(01)00332-x

Cited by 146 publications

(68 citation statements)

References 33 publications

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“…where D ¼ 4pm*/h 2 is the conduction band density of states of a 2-D system, k B is the Boltzmann's constant, m* is the electron effective mass (m* ¼ 0.22m o ), m o is the electron rest mass, h is Planck's constant, T is the absolute temperature, E F is the Fermi energy and the allowed energy levels in the triangular quantum well are E i ¼ c i n s 2/3 (eV) for i ¼ 0.1 with c 0 ¼ 2.123 Â 10 À12 and c 1 ¼ 3.734 Â 10 À12 [10]. Equation (1) shows the relationship between the sheet carrier density, n s , and the Fermi level E f , and assumes a triangular potential well with only the first two quantum states (E 1 and E 0 ) being occupied.…”

Section: A Charge Controlmentioning

confidence: 99%

“…where m is the aluminum mole fraction, e(m) is the dielectric constant of AlGaN, d d is the thickness of the doped AlGaN barrier layer, d i is the thickness of the undoped AlGaN spacer layer, Dd is the effective width of the 2DEG, q is the electron charge, V gs is the applied gate-to-source voltage, and V th (m) is the polarization-dependent threshold voltage given as [10],…”

Section: A Charge Controlmentioning

confidence: 99%

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A physics-based model of DC and microwave characteristics of GaN/AlGaN HEMTs

Sippel

Islam

Mukherjee

2007

Int J RF and Microwave Comp Aid Eng

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A physics-based model of AlGaN/GaN High Electron Mobility Transistor (HEMT) is developed for the analysis of DC and microwave characteristics. Large-and small-signal parameters are calculated for a given device dimensions and operating conditions. Spontaneous and piezoelectric polarizations at the heterointerface and finite effective width of the 2DEG gas have been incorporated in the analysis. The model predicts a maximum drain current of 523 mA/mm and transconductance of 138 mS/mm for a 1 mm 3 75 lm device, which are in agreement with the experimental data.

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Section: A Charge Controlmentioning

confidence: 99%

Section: A Charge Controlmentioning

confidence: 99%

A physics-based model of DC and microwave characteristics of GaN/AlGaN HEMTs

Sippel

Islam

Mukherjee

2007

Int J RF and Microwave Comp Aid Eng

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show abstract

“…(11) we get E 0 (eV ) = 1.35865 × 10 −6 (E well ) 2/3 (12) E 1 (eV ) = 2.39015 × 10 −6 (E well ) 2/3 (13)…”

Section: Dependence Of Eigenenergy On E Wellmentioning

confidence: 94%

“…But charges due to both spontaneous and piezoelectric polarization process are highly responsible for formation of more 2DEG density in AlGaN/GaN system by a factor of 10 over the AlGaAs/GaAs system [11] without the cost of doping. Rashmi et al [12] developed an appropriate charge control model for n s formed in triangular quantum well subject to both strong and weak inversion mode considering polarization charges. But as MOSHEMT state of the art technology is recently developed, till date to the best of the author's knowledge no model explains the dependence of n s on oxide layer parameters.…”

Section: Introductionmentioning

confidence: 99%

Modeling and simulation of oxide dependent 2DEG sheet charge density in AlGaN/GaN MOSHEMT

et al. 2015

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Oxide dielectric present in metal oxide semiconductor high electron mobility transistor plays an important role during formation of two dimensional electron gas (2DEG). The sheet charge concentration (n s ) is dependent on the Eigenenergy states present in triangular quantum well at AlGaN/GaN interface. The energy states are in fact functions of vertical electric field at the edge of the well. Therefore in this paper a model is developed to find out Electric field and flat-band voltage (V T ) by adopting energy band approach to incorporate oxide parameters in it unlike the conventional method of solving Poisson's equation, which is the uniqueness of this paper. The Eigenenergy states are dependent non-linearly on electric field. In the present case, three quantum states in the well are considered along with the Fermi-Dirac distribution function to obtain n s . The dependence of 2DEG density, electric field and flat-band voltage on the oxide parameters such as thickness and electrical permittivity is analyzed. With respect to thickness in SiO 2 and Al 2 O 3 , n s shows inverse relationship; whereas in HfO 2 it is direct due to positive charges accumulated at oxide/barrier interface. To the best of author's knowledge the work is first of its kind and due to lack of experimental data; the obtained results are compared with TCAD results to validate the model.

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“…In 2002, Rashmi [30] deduced some approximate expression from equation (6) appropriating for different region of operation which obviously, is not convenient for application. Although the approximation has improved a lot, but all of above analytical expressions for EF versus ns have been proposed so far have disadvantages more or less, such as can not appropriate for a large range of values of ns, the results are not accurate enough for modeling and so on.…”

Section: Relation Between Fermi Level and Surface Charge Densitymentioning

confidence: 99%

Analytical Surface Charge Control Model for AlN/GaN/AlGaN Double Heterojunction Field-Effect Transistor

Khan¹

2013

JEEE

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Abstract:We have argued that the nature of surface potential variation with gate voltage of AlN/GaN/AlGaN Double Heterojunction Field Effect Transistor (DHFET) is no different from that of the conventional GaAs/AlGaAs HEMT devices. Necessary simulated band diagrams have been presented to justify our claim and we have also proposed a nonlinear expression for Fermi level (E F ) variation with the two-dimensional electron gas density (2DEG). We have showed that our proposed expression provides better agreement with the numerical solution than the previous approximations. Besides, expression of surface charge density (n s ) variation with gate voltage (V G ) obtained using our proposed model, shows better fit with the numerical simulation data in wide range of bias conditions.

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An accurate charge control model for spontaneous and piezoelectric polarization dependent two-dimensional electron gas sheet charge density of lattice-mismatched AlGaN/GaN HEMTs

Cited by 146 publications

References 33 publications

A physics-based model of DC and microwave characteristics of GaN/AlGaN HEMTs

A physics-based model of DC and microwave characteristics of GaN/AlGaN HEMTs

Modeling and simulation of oxide dependent 2DEG sheet charge density in AlGaN/GaN MOSHEMT

Analytical Surface Charge Control Model for AlN/GaN/AlGaN Double Heterojunction Field-Effect Transistor

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