DIELECTRIC-PROPERTIES OF ELECTRON-BEAM DEPOSITED GA2O3 FILMS

We have fabricated high quality, dielectric Ga2O3 thin films. The film s with thicknesses between 40 and 4000 angstrom were deposited by elec tron-beam evaporation using a single-crystal high purity Gd3Ga5O12 sou rce. Metal-insulator-semiconductor (MIS) and metal-insulator-metal str uctures (MIM) were fabricated in order to determine dielectric propert ies, which were found to depend strongly on deposition conditions such as substrate temperature and oxygen pressure. We obtained excellent d ielectric properties for films deposited at substrate temperatures of 40-degrees-C with no excess oxygen and at 125-degrees-C with an oxygen partial pressure of 2X10(-4) Torr. Specific resistivities rho and dc breakdown fields E(m) of up to 6X10(13) OMEGA cm and 2.1 MV/cm, respec tively, were measured. Static dielectric constants between 9.93 and 10 .2 were determined for these films. Like in other dielectrics, the cur rent transport mechanisms are found to be bulk rather than electrode c ontrolled.