Abstract: An electrode structure, a GaN-based semiconductor device including the electrode structure, and methods of manufacturing the same, may include a GaN-based semiconductor layer and an electrode structure on the GaN-based semiconductor layer. The electrode structure may include an electrode element including a conductive material and a diffusion layer between the electrode element and the GaN-based semiconductor layer. The diffusion layer may include a material which is an n-type dopant with respect to the GaN-based semiconductor layer, and the diffusion layer may contact the GaN-based semiconductor layer. A region of the GaN-based semiconductor layer contacting the diffusion layer may be doped with the n-type dopant. The material of the diffusion layer may comprise a Group 4 element.

Abstract: A semiconductor device includes a channel region 18 of semiconductor, a conductive gate electrode 12 adjacent to the channel region 18 and a gate dielectric 10 between the conductive gate electrode 12 and the channel region 18. The gate dielectric 10 is formed of a material that is a ferroelectric in bulk but in a superparaelectric state. The gate dielectric may be for instance of formula AXO3, where A is a group I or II element, and X is titanium, niobium, zirconium and/or hafnium. Such a gate dielectric 10 may be formed for example by low temperature deposition of the gate dielectric 10 or by using dopants of metal oxides to prevent domain growth, or both.