Lateral epitaxial overgrowth of GaN on Si(111). Progress report
The lateral epitaxial overgrowth of GaN on Si(111) substrates was achieved using an extension of the standard LEO process on GaN/Al{sub 2}O{sub 3} substrates, and the reduction of the dislocation density was demonstrated by transmission electron microscopy (TEM) and atomic force microscopy (AFM). The growth on the Si(111) substrate was initiated with the deposition of a thin AlN buffer layer to avoid the formation of potentially detrimental silicon nitride at the interface. The wafers were then patterned with a SiO{sub 2} layer in which 5 micron wide opening separated by 35 microns were etched using buffered HF. After reloading the samples in the MOCVD chamber, the LEO growth was performed using the authors` standard parameters. There are a few unresolved issues concerning the effect of the AlN buffer thickness and its chemical compatibility with the SiO{sub 2} mask layer, but after a basic optimization they were able to obtain 5 microns of lateral overgrowth with smooth sidewalls in a reproducible manner. They are currently investigating the use of mask materials other than SiO{sub 2} to achieve LEO on Si(111) over a wider range of process parameters.
- Research Organization:
- California Univ., Santa Barbara, CA (United States)
- OSTI ID:
- 676177
- Report Number(s):
- AD-A--353896/XAB
- Country of Publication:
- United States
- Language:
- English
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