Wafer bow during GaN on Si growth on sapphire
In his talk Christoph Berger explained, how the researchers of the OvG University in Magdeburg use the EpiCurve® TT technology for developing optimized processes for III-N growth on silicon. Specifically, they targeted the reduction of the density of threading dislocations (TDs) in the devices and the reduction of the final silicon wafer bow for subsequent processing. In Fig.1 (see newsletter) it is shown, how the effect of SiN in-situ masking was closely followed by using the wafer curvature response to a fixed Si doping (8x1018cm-3) as a measure for the remaining TDs in the material. By the way: new knowledge about the physics behind this effect was discussed also during the ICNS conference in two remarkable contributions:
Dr. M.A. Moram of Cambridge university presented in her talk the latest results on dopant segregation at GaN dislocations (based on ex-situ TEM and XRD results) and Dr. Frank Brunner could verify in his talk on doping induced wafer bow in III-N on sapphire, that at least two mechanisms, TD reduction and opand induced surface roughening, contribute to the wafer bow response to Si doping (based on EpiCurve® TT wafer bow and 405nm reflection data).
Please find the figure to this article and more news in the latest newsletter >
If you're interested in Mr. Berger's talk please ask us for the presentation >