GROWTH OF MAGNESIUM OXIDE AND SCANDIUM OXIDE ON GaN FOR USE AS GATE AND FIELD PASSIVATION DIELECTRICS

摘要

The substrate preparation of gallium nitride, both ex-situ and in-situ, and the growth of magnesium oxide, MgO, and scandium oxide, Sc_2O_3, by plasma assisted gas-source molecular beam epitaxy (GSMBE) are presented. These oxides are employed as field passivation of AlGaN/GaN high electron mobility transistor (HEMT) devices and gate dielectrics for test diodes and metal oxide semiconductor HEMTs (MOSHEMTs). Ex-situ cleaning techniques include wet chemical etching and UV-ozone treatments and in-situ techniques include thermal and plasma treatments. Various growth recipes have been explored to produce MgO and Sc_2O_3 films with different morphologies and stoichiometry. The end result is a dielectric material with an oxideitride interface with low interface trap density and interface stability to allow for inversion to be demonstrated in GaN as well as reduce the current collapse phenomenon to minimum impact on HEMT device operation.