On the use of remote RF plasma source to enhance III–V MOCVD technology

A remote RF (13.56 MHz) plasma source, assembled on a metalorganic chemical vapour deposition (MOCVD) system, was used to investigate the processes of (a) cleaning and passivation of InP substrates with H atoms (H₂ plasmas), (b) deposition of InP epilayers from In(CH₃)₃ and PH_x radicals (PH₃/H₂ plasmas), and (c) deposition of InN on sapphire from In(CH₃)₃ and N atoms (N₂---H₂---Ar plasmas). From kinetic and spectroscopic ellipsometric in situ analysis, the removal of native oxide from InP surface was found to be complete, without surface damage (phosphorus depletion), at 230°C and 7 min of H atoms exposure. The growth of InP epilayers with PH₃ plasma pre-activation was successful (stoichiometric InP) even at low V/III ratio. During InN growth, the use of optical emission spectroscopy (OES) and of in situ ellipsometry (SE) was determinant for the process control.