SOURCE/DRAIN-ON-INSULATOR (S/DOI) FIELD EFFECT TRANSISTOR USING SILICON NITRIDE AND SILICON OXIDE AND METHOD OF FABRICATION

摘要

Source (7) and drain (6) regions of field effect transistors are fabricated with an electrically insulating layer (8, 9) formed thereunder so as to reduce junction capacitance between each and a semiconductor body (3) in which the regions are formed. One method of fabrication of the source and drain regions is to form an isolating isolation region (5) around active areas in which a transistor is to be formed in a semiconductor body. Trenches separated by portions of the body are then formed in the active areas in which transistors are to be formed. On bottom surfaces of the trenches are formed an electrically insulating layer. The trenches are then filled with semiconductor material of a conductivity type opposite that of the semiconductor body. The semiconductor filled portion of each trench then serves as a drain and/or source (6, 7) of a field effect transistor.