ABSTRACT
Silicon-on-insulator or semiconductor-on-insulator (SOI) refers to a class of structures where active thin film Si devices (semiconductor devices) are supported by an insulating material, resulting in a dielectrically isolated device structure. Insulators used in the SOI structure must be stable during heat treatments for epitaxial growth and device fabrication, in order for their electrical properties such as resistivity, breakdown field, and dielectric constant to be sufficient. SOI structures can also be formed by oxidation of buried porous Si, which is converted from single crystal Si by anodization in Hydrofluoric acid. In the full isolation by porous oxidized silicon (FIPOS) method, however, the thickness of the porous Si layer becomes thicker as the Si island becomes larger, because of the isotropic anodization. Heteroepitaxial growth of semiconductor films on single crystalline insulators has advantages such that there is no essential limitation on the size of SOI regions and it can easily be applied to the growth of compound semiconductors.
