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. 21, 2002
Filed:
Jan. 14, 2000
Hsueh-Rong Chang, Thousand Oaks, CA (US);
Rockwell Science Center, LLC, Thousand Oaks, CA (US);
Abstract
A trench insulated-gate bipolar transistor (IGBT) comprises a number of trench-IGBT structures interdigitated with bipolar transistor (BJT) structures in a drift layer, with trench gates separating the structures. Shallow P regions span the bottom corners of respective trench gates to protect the trench oxide from high peak electric fields encountered when the device is reverse-biased. Because no inversion channels form across the BJT mesas in response to a gate voltage, base drive and thus the device's saturation current level is reduced and a robust short-circuit SOA is provided. The ratio of IGBT structures to BJT structures is adjusted as needed to obtain a desired saturation current level and short-circuit SOA. The higher forward voltage drop incurred by the introduction of BJT structures is countered by increasing the depth of the trench gates, causing longer accumulation channels to form along the gates' sidewalls which enhance the device's injection efficiency and lower its forward voltage drop. An N-type layer extending above and below the shallow P regions counters the increase in on-resistance brought about by their encroachment into the IGBT and BJT mesas.