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1993
Journal Article
Titel
ECR plasma deposition of cubic nitride using n-trimethylborazine
Abstract
N-Trimethylborazine has been used as a precursor in a downstream ECR plasma process to deposit cubic BN.N-Trimethylborazine (B3N3H3(CH3)3)is a noncorrosive and non-explosive liquid with a low toxicity. As plasma gas an argon/nitrogen mixture was used and N-trimethylborazine vapour was fed into the downstream region of the ECR plasma source. BN deposits on silicon (111) were characterized by IR spectroscopy, EPMA, and XRD. The formation of nanocrystalline c-BN strongly depends on the process parameters and needs a substrate temperature of bigger than 800 degree C. Furthermore the application of a negative substrate bias, in our experiments achieved with a low frequency (100-450 kHz) generator, is essential to increase the c-BN fraction of the deposit. As shown by IR spectroscopy a stepwise transition from hexagonal BN into wunzite-type BN and finally into cubic BN takes place by changing the deposition conditions. From these observations some conclusions concerning the growth mechanism of cubic BN can be derived. Due to the merits of N-trimethylborazine its processing - compared to diborane or borontrihalides - is uncomplicated and promising for future applications of cubic BN.