Uniform current density and high current gain bipolar transistor
US5554880A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 8, 1994 |
| Grant date | Sep 10, 1996 |
| Priority date | — |
| Expiry date | Aug 8, 2014 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH10D10/00
Abstract
The present invention discloses method for fabricating, and the structure of, a unique and novel bipolar transistor. The bipolar transistor of the present invention has a substantially uniform current density in base and collector regions. This uniform current density prevents the characteristic early fall-off of bipolar transistor current gain, and improves the forward safe operating area performance. As such, the bipolar transistor of the invention increases current gain at high collector currents, and expands the current and voltage region over which the device may safely operated. The advantages of the present invention are achieved by optimally spacing the neighboring emitters in relation to base thickness and further by maintaining a symmetrical topology by the self-aligned formation of emitters and base contacts. According to the invention, the emitters are optimally spaced so that the current emanating from an emitter would fill base and collector regions beneath and beside the emitter in a fashion to provide a uniform current distribution. As such, the entire base and collector regions below the center of a given emitter conduct the emitter majority carrier current in a su…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.