DESIGN METHODOLOGY FOR MULTIPLE CHANNEL HETEROSTRUCTURES IN POLAR MATERIALS

摘要

A method for fabricating multiple channel heterostructures with high sheet carrier densities in each channel (L1, L3, L5), while maintaining a low energy barrier for transfer of majority carriers between the channels (L1, L3, L5). For a heterostructure where n-type conductivity is desired, n-type dopant impurities are placed at each heterointerface (I2, I4) with negative polarization charge, equal in magnitude to the negative polarization charge. For a heterostructure where p-type conductivity is desired, p-type dopant impurities are placed at each heterointerface (I2, I4) with positive polarization charge, equal in magnitude to the positive polarization charge. The heterointerfaces (I2, I4) with dopant impurities can be graded in chemical composition, over a certain distance, while the dopant impurities are distributed along the graded distance. The heterointerfaces (I2, I4) with dopant impurities can also be abrupt, in which case the dopant impurity is located in a sheet or thin layer at or near the heterointerface (I2, I4).