The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
May. 11, 2004
Filed:
May. 27, 2003
Kinya Ohtani, Kawasaki, JP;
NEC Electronics Corporation, , JP;
Abstract
A vertical field effect transistor includes an N.sup.+semiconductor substrate and an N.sup.−epitaxial layer deposited thereon and having lower dopant concentration than the semiconductor substrate, and is configured to have a plurality of unit cell transistors formed in the N.sup.−epitaxial layer and arranged in the epitaxial layer in longitudinal and lateral directions. The unit cell transistor includes a trench formed to have a depth X.sub.a and a width W, and further a gate electrode formed within the trench and interposing a gate insulating film that has a thickness T.sub.OX and formed between the gate electrode and the surface of the trench. Moreover, the unit cell transistor includes a P-type base region having a depth X.sub.b, a source region, a heavily doped P-type base region formed in a central portion of the cell transistor and having a depth X.sub.c, and an gate insulating film (in this case, gate oxide film) formed facing the surface of the trench, in which those components are formed so as to satisfy mathematical relationships represented by X.sub.b<X.sub.a and X.sub.a≈X.sub.c. The unit cell transistor is further constructed such that when assuming spacing between the trench and the heavily doped P-type region is L.sub.td, the trench and the heavily doped P-type region are formed so as to satisfy a mathematical relationship represented by L.sub.td≦2.times.(X.sub.a−X.sub.b).