Manufacturing gallium nitride substrates by lateral overgrowth through masks and devices fabricated thereof
US7445673B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | May 18, 2004 |
| Grant date | Nov 4, 2008 |
| Priority date | — |
| Expiry date | Jul 21, 2024 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01L21/02647
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
Gallium nitride substrates are grown by epitaxial lateral overgrowth using multiple steps. On a masked substrate having openings areas, selective growth produces first triangular stripes in which most of the threading dislocations are bent at 90°. In a second step, growth conditions are changed to increase the lateral growth rate and produce a flat (0001) surface. At this stage the density of dislocations on the surface is <5×107 cm 2. Dislocations are primarily located at the coalescence region between two laterally grown facets pinching off together. To further decrease the dislocation density a second masking step is achieved, with the openings exactly located above the first ones. Threading dislocations (TDs) of the coalescence region do not propagate in the top layer. Therefore the density of dislocations is lowered below <1×107 cm lover the entire surface.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.