Stabilization of Indium-Rich In1-xGaxN Heterostructures: The Exploration of a Common Processing Window
Final rept. 1 Apr 2010-31 Mar 2015
GEORGIA STATE UNIV ATLANTA DEPT OF PHYSICS AND ASTRONOMY
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During the grant period, the growth and optimization of indium-rich InGaN layers grown by high-pressure metalorganic chemical vapor deposition MOCVD was explored at reactor pressures from 5 to 20 bar and at growth temperatures of 700-900 deg C. The goal was to evaluate the reactor pressure and growth temperature relation at which indium-rich In1-xGaxN layers can be stabilized. The results showed that for a pressure at 15 bar, the growth temperatures for InGaN varies from 850 deg C InN to 950 deg C In0.7Ga0.3N, reducing the temperature gap in the ternary InGaN system compared to low-pressure MOCVD. An unexpected effect was the significant reduction in growth rate with increasing reactor pressures, which is due to smaller surface diffusion layers with incr. pressures. The results on forming single phase InGaN alloys using simultaneous and sequential group-III precursor injection sequences worked only partially We obtained single phase alloys for In1-xGaxN 0x0.15 and 0.25x0.3 but mixed phases between. The experiments indicate the presence of Ga- and In-adlayers that may play a major role for the observed mixed InGaN phases. Additional studies will be needed to relate the precursor deployment with surface decomposition and surface chemistry processes.
- Solid State Physics