DPG Phi
Verhandlungen
Verhandlungen
DPG

Hamburg 2001 – wissenschaftliches Programm

Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe

HL: Halbleiterphysik

HL 23: GaN I

HL 23.3: Vortrag

Dienstag, 27. März 2001, 16:00–16:15, S2

Flow modulation growth of GaN by hydride vapor phase epitaxy — •Wei Zhang1, Helder R. Alves1, Dirk Meister1, Detlev M. Hofmann1, Bruno K. Meyer1, Till Riemann2, Peter Veit2, Alois Krost2, and Juergen Christen21I. Physics Institute, Justus-Liebig-University Giessen — 2Institute of Experimental Physics, Otto-von-Guericke- University Magdeburg

Conventional growth of GaN films on Al2O3 substrates tends to result in high threading dislocation densities (108 - 1010 cm−2) and unsatisfactory morphology of the films due to the large lattice mismatch between GaN and the substrate. Techniques using buffer layers, pretreatments of the substrate and epitaxial lateral overgrowth have recently been applied to improve the crystaline quality of GaN. In this work we demonstrate the effect of flow modulation on the growth of thick GaN by hydride vapor phase epitaxy (HVPE) to reduce the dislocation density and to improve layer morphology. The flow modulation growth was carried out in a custom vertical HVPE system. The reactive species were injected periodically into the reactor to realize the modulation of the flow. Optical microscopy shows that the GaN films are very smooth, almost crack-free. Cathodoluminescence and transmission electron microscopy of the cross-sectional structure exhibit that there is a seperated multilayer structure in the GaN films. The dislocation density decreases from 1010 cm−2 in the initial layer to 107 cm−2 in the top layer. This shows that flow modulation growth is a useful technique to improve the cystaline quality of thick GaN films.

100% | Mobil-Ansicht | English Version | Kontakt/Impressum/Datenschutz
DPG-Physik > DPG-Verhandlungen > 2001 > Hamburg