A semiconductor device has an element substrate including a semiconductor layer of a first conductivity type being formed over a semiconductor substrate with a dielectric film interposed therebetween. A groove is formed in the element substrate with a depth extending from a top surface of the semiconductor...http://www.google.de/patents/US6906372?utm_source=gb-gplus-sharePatent US6906372 - Semiconductor device with vertical transistor formed in a silicon-on-insulator substrate
