Tailoring of internal fields in AlGaN/GaN and InGaN/GaN heterostructure devices

A study of the internal electric field distributions in AlxGa1-xN/GaN and I nxGa1-xN/GaN heterostructures grown on (0001) GaN is presented. The fields are deduced taking into account the device structure, background doping, an d the difference in the total (spontaneous and piezoelectric) polarization of the layers. Two basic structures, a multiple quantum well in the depleti on region of a p-n junction and the heterojunction field effect transistor, are analyzed. The cases where the field distribution can be approximated a nalytically are discussed. When charge accumulation is present at the inter faces, a self-consistent solution of the Schrodinger and Poisson equations is obtained. By comparing with available experimental data, the polarizatio n field in AlxGa1-xN/GaN heterostructures has been estimated for two Al con tents.