The surface nitridation of GaAs and sapphire substrates and the growth of GaN buffer layers in a remote r.f. plasma MOCVD apparatus are investigated in real lime by in situ spectroscopic ellipsometry. Substrates are at first in situ cleaned by H-2 plasmas, then are nitrided by N-2 or N-2-H-2 plasmas at low temperature and afterwards the GaN buffer layer growth by GaMe3 and N-2-H-2 plasmas is performed at T = 600 degrees C. The role of the surface temperature on the nitridation depth, on the substrate/GaN interface composition and morphology is highlight by ellipsometry. Also, the initial stage of the GaN buffer growth is described in terms of nucleation. Ga-enrichment and of GaN/GaAs interface degradation.
In situ real time ellipsometry monitoring during GaN epilayers processing
1999
Abstract
The surface nitridation of GaAs and sapphire substrates and the growth of GaN buffer layers in a remote r.f. plasma MOCVD apparatus are investigated in real lime by in situ spectroscopic ellipsometry. Substrates are at first in situ cleaned by H-2 plasmas, then are nitrided by N-2 or N-2-H-2 plasmas at low temperature and afterwards the GaN buffer layer growth by GaMe3 and N-2-H-2 plasmas is performed at T = 600 degrees C. The role of the surface temperature on the nitridation depth, on the substrate/GaN interface composition and morphology is highlight by ellipsometry. Also, the initial stage of the GaN buffer growth is described in terms of nucleation. Ga-enrichment and of GaN/GaAs interface degradation.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
