A two-dimensional model for the potential distribution and depletion layer width of the short gate-length GaAs MESFET´s

A new two-dimensional analytical model for the potential distribution and depletion-layer width for the short-gate GaAs MESFET´s has been presented in this paper. The solution of the two-dimensional Poisson´s equation has been considered as the superposition of the solution of one-dimensional Poisson´s equation in the lateral direction and the two-dimensional Laplace equation with suitable boundary conditions. The remarkable feature of the proposed model is that, in the hand the simplicity of the mathematical expressions and in the other hand the acceptable distribution for the potential and charge in the channel. The numerical results have been presented for the potential distribution and depletion-layer width for different parameters such as the drain-source voltage, gate-length, active-layer thickness and doped profile. It is observed that for the GaAs MESFET´s, as the gate-length is decreased, the 2-D potential is increased and this demonstrates the importance of the two-dimensional analysis for the short-gate devices.