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

Abstract

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.

Modeling and simulation of 2DEG density and intrinsic capacitances in AlInN/GaN MOSHEMT

“…It is observed here that the 2DEG density is increasing with increase in oxide thickness . Physically, because of positive charges present at HfO 2 bulk and interface, the magnitude of electric field in the quantum‐well decreases with increase in oxide thickness, which decreases the subband energy and increases n s . Good agreement between model and TCAD results is observed, which makes it very convenient to develop the expressions for terminal charges as per Equation .…”

Oxide interfacial charge engineering towards normally-off AlN/GaN MOSHEMT

“…5 which shows a V T of around 0 V and I d of 540 mA/mm at V ds ¼1 V. Realization of more drain current is due to more 2DEG formed as compared to Al 2 O 3 and SiO 2 for same oxide thickness of 2 nm and barrier thickness of 2 nm [26]. In Fig.…”

Analytical Model Development for Unified 2D Electron Gas Sheet Charge Density of AlInN/GaN MOSHEMT

“…The increasing linearly with positive slope when increasing the oxide thickness. When the oxide thickness is increasing, the electric field decreases due to the existence of positive interface and bulk oxide charges in 2 material [7]. When the electric field decreases the quantum-well sub-band energy values decreases then the difference increases and in consequence to increase in .…”

“…Lenka is with Department of Electronics and Communication Engineering, National Institute of Technology, Silchar, India (e-mail: amarnath.nits@gmail.com). material as SiN [4], SiO2 [5], Al2O3 [6], HfO2 [7], La2O3 [8], AlN [9], LaLuO3 [10], MgCaO [3]. Among these oxides, HfO2 is considered in this work.…”