Patent ID: 6660616
Filing Date: 2003-12-09
Classification: H01L

Abstract:
A method of forming a transit time device in a semiconductor layer overlying an insulator layer, comprising the steps of:masking the semiconductor layer to expose a first selected location of the semiconductor layer; doping the exposed first selected location to a first conductivity type; masking the semiconductor layer to expose a second selected location of the semiconductor layer, the first and second selected locations separated from one another by a distance; doping the exposed second selected location to a second conductivity type, so that a portion of the semiconductor layer remaining between the first and second doped selected locations corresponds to an intrinsic region; forming an isolation structure to surround the first and second doped selected locations and the intrinsic region; doping the intrinsic region to a lightly-doped doping concentration relative to the first and second doped selected locations; after the doping steps, forming an epitaxial layer over the semiconductor layer; removing selected portions of the epitaxial layer, leaving first and second sinker structures overlying and in contact with the first and second doped selected locations of the semiconductor layer; and doping the first and second sinker structures to the first and respectively, so that said first and second sinker structures become the first and second conductivity types, respectively, wherein said first conductivity types is opposite to said second conductivity type.