Remote plasma assisted MOCVD growth of GaN on 4H-SiC: growth mode characterization exploiting ellipsometry

¹ Institute of Inorganic Methodologies and of Plasmas, IMIP-CNR and INSTM UdR Bari, via Orabona, 4, 70126 Bari, Italy
² Department of Electrical and Computer Engineering, Duke University, Durham, NC 27709, USA

Corresponding author: maria.losurdo@ba.imip.cnr.it

Received: 14 April 2005
Revised: 26 May 2005
Accepted: 8 June 2005
Published online: 14 September 2005

Abstract

GaN is grown on Si-face 4H-SiC(0001) substrates using remote plasma-assisted metalorganic chemical vapour deposition (RP-MOCVD). The pre-dissociation of nitrogen by the remote plasma is used for lowering the deposition temperature to approximately 700 °C. Remote plasma processing is also used for SiC surface pre-treatments including a low-temperature atomic hydrogen cleaning (by remote H₂ plasma) and nitridation (by remote N₂ plasma). Furthermore, in situ spectroscopic ellipsometry is used for monitoring in real time all the steps of substrate pre-treatments and the heteroepitaxial growth of GaN on SiC. Our characterization emphasis is on understanding the nucleation mechanism and the GaN growth mode, which depend on the SiC surface preparation.