Two-dimensional drift-diffusion simulation of GaN HFETs

The electron transport properties of AlGaN/GaN heterojunction field effect transistors (HFETs) were studied by two-dimensional drift-diffusion (DD) modeling method. The model performs self-consistent numerical computation on the Poisson equation, carrier statistics and current and continuity equations. The spontaneous and piezoelectircal polarization charges uniquely for GaN material was taken into account, which influences significantly the electron distribution and current density. Sliced 1D Schrödinger equation along c direction was solved to obtain electron distribution. The electrical field at the 2DEG channel was found to have a peak position locates at the gate edge towards the drain side, reaching 106 V/cm at high bias condition. The surface potential boundary conditions also were found to have profound influence to the simulation results.

[1]  Shreepad Karmalkar,et al.  Enhancement of breakdown voltage in AlGaN/GaN high electron mobility transistors using a field plate , 2001 .

[2]  Yoshiki Yano,et al.  Recess gate AlGaN/GaN HEMTs using overlap gate metal structure , 2010 .

[3]  Y. Saad,et al.  GMRES: a generalized minimal residual algorithm for solving nonsymmetric linear systems , 1986 .

[4]  Debdeep Jena,et al.  Polarization Effects in Semiconductors: From Ab Initio Theory to Device Applications , 2007 .

[5]  F. Bernardini,et al.  First-principles prediction of structure, energetics, formation enthalpy, elastic constants, polarization, and piezoelectric constants of AlN, GaN, and InN: Comparison of local and gradient-corrected density-functional theory , 2001 .

[6]  Peter A. Houston,et al.  High temperature performance of AlGaN/GaN HEMTs on Si substrates , 2006 .

[7]  M. Uren,et al.  Measurements of unity gain cutoff frequency and saturation velocity of a GaN HEMT transistor , 2005, IEEE Transactions on Electron Devices.

[8]  U. Mishra,et al.  30-W/mm GaN HEMTs by field plate optimization , 2004, IEEE Electron Device Letters.

[9]  Tom M. Apostol,et al.  Calculus, volume II : multi - variable and linear algebra, with application to differential equations and probability / Tom M. Apostol , 1969 .

[10]  W. Hänsch,et al.  The drift diffusion equation and its applications in MOSFET modeling , 1991 .

[11]  A. Chini,et al.  High breakdown voltage AlGaN-GaN HEMTs achieved by multiple field plates , 2004, IEEE Electron Device Letters.

[12]  F. Bernardini,et al.  Accurate calculation of polarization-related quantities in semiconductors , 2001 .

[13]  H. Gummel.  A self-consistent iterative scheme for one-dimensional steady state transistor calculations , 1964 .