Monolithic semiconductor device having CCD, bipolar and MOS structures
US4994888A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 18, 1990 |
| Grant date | Feb 19, 1991 |
| Priority date | — |
| Expiry date | May 18, 2010 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH10D84/891
Abstract
A semiconductor device comprising a semiconductor chip formed of a substrate of a first conductivity type and an epitaxial layer of the first conductivity type formed on the substrate, a charge transfer device section formed in the epitaxial layer and driven by a given clock, and a preset region of a second conductivity type formed adjacent to the charge transfer device section in the semiconductor ship. The preset region includes a first layer of the second conductivity type formed in a boundary portion between the substrate and the epitaxial layer, a second layer of the second conductivity type formed on the first layer the epitaxial layer, and a third layer of the second conductivity type formed on the second layer in the epitaxial layer to reach the surface of the substrate. The maximum value of the second conductivity type impurity concentration of the third layer is set smaller than the maximum value of the second conductivity type impurity concentration of the first layer. A bipolar transistor section is formed in the third layer.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.