Formation of a high aspect ratio trench in a semiconductor substrate and a bipolar semiconductor device having a high aspect ratio trench isolation region
US9059234B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Oct 22, 2013 |
| Grant date | Jun 16, 2015 |
| Priority date | — |
| Expiry date | Oct 22, 2033 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH10D62/822
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
Disclosed is a trench formation technique wherein a first etch process forms an opening through a semiconductor layer into a semiconductor substrate and then a second etch process expands the portion of the opening within the substrate to form a trench. However, prior to the second etch, a doped region is formed in the substrate at the bottom surface of the opening. Then, the second etch is performed such that an undoped region of the substrate at the sidewalls of the opening is etched at a faster etch rate than the doped region, thereby ensuring that the trench has a relatively high aspect ratio. Also disclosed is a bipolar semiconductor device formation method. This method incorporates the trench formation technique so that a trench isolation region formed around a collector pedestal has a high aspect ratio and, thereby so that collector-to-base capacitance Ccb and collector resistance Rc are both minimized.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.