Simulation of Tunneling Contact Resistivity in Non-polar AlGaN/GaN Heterostructures

We have evaluated the tunneling contact resistivity based on numerical calculation of tunneling current density across an AlGaN barrier layer in non-polar AlGaN/GaN heterostructures. In order to reduce the tunneling contact resistivity, we have introduced an n-AlXGa1−XN layer between an n-GaN cap layer and an i-AlGaN barrier layer. The tunneling contact resistivity has been optimized by varying Al composition and donor concentration in n-AlXGa1−XN. Simulation results show that the tunneling contact resistivity can be improved by as large as 4 orders of magnitude, compared to the standard AlGaN/GaN heterostructure. key words: GaN, HEMT, potential barrier, contact resistance, tunneling current density