In situ mass spectrometric diagnostics during InP deposition in a remote plasma-enhanced MOCVD system

In conventional MOCVD systems, high deposition temperatures are needed to supply the activation energy for both gas phase and surface reactions, and to produce epitaxial growth material with good morphology. Recently, there has been an increased interest on the use of the plasma, in remote configuration, to enhance the MOCVD process for the growth of III-V materials (1). The plasma, as a secondary source of energy, offers low temperature and low V/III ratio processing, mainly by the pre-cracking of the thermally relatively stable hydrides PHQ or AsH ₃. Remote plasma processes are also receiving increased attention for other applications such as: (a) the substrate cleaning, for the removal of native oxides on InP and GaAs surface by hydrogen plasma treatment (2,3), and (b) the in situ generation of PHQ through the ablation of red-phosphorus in H₂ plasma (4,5). These RPE-MOCVD processes can operate in a wide range of parameters (pressure, r.f. power, gas flow, geometry, frequency, temperature) and the knowledge and understanding of the plasma chemistry controlling the production of reactive species are still far from being complete. In this work we present our first observations on a laboratory RPE-MOCVD reactor for the deposition of InP from PHQ and InMe₃. Mass spectrometry (MS) was used to investigate the in situ production of PH ₃, the plasma pre-cracking of PH₃ and the InP growth process. The optical emission spectroscopy (OES) was also used for the analysis of the emitting species present in the plasma phase