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Influence of Diamond CVD Growth Conditions and Interlayer Material on Diamond/GaN Interface

MetadataDetails
Publication Date2015-06-30
JournalMaterials science forum
AuthorsTibor Ižák, Oleg Babchenko, Vı́t Jirásek, G. Vanko, Marián Vojs
InstitutionsSlovak University of Technology in Bratislava, Czech Academy of Sciences
Citations8

In this study we present the diamond deposition on AlGaN/GaN substrates focusing on the quality of the diamond/GaN interface. The growth of diamond films was performed using microwave chemical vapour deposition system in different gas mixtures: standard CH 4 /H 2 (at low and high ratio of CH 4 to H 2 ) and addition of CO 2 to CH 4 /H 2 gas chemistry. The diamond films were grown directly on GaN films either without or with thin interlayer. As interlayer, 100 nm thick Si 3 N 4 was used. Surprisingly, in the case of standard CH 4 /H 2 gas mixture, no diamond film was observed on the GaN with SiN interlayer, while adding of CO 2 resulted in diamond film formation of both samples with and without SiN interlayer. Moreover, adding of CO 2 led to higher growth rate. The morphology of diamond films and the quality of the diamond/GaN interface was investigated from the cross-section images by scanning electron microscopy and the chemical character (i.e. sp 3 versus sp 2 carbon bonds) was measured by Raman spectroscopy.