Reduction of vacuum sublimation by ion beam treatment for e-beam deposited SiC films

We report on the low temperature (≤1000 °C) vacuum sublimation behavior of e-beam evaporative deposited SiC film and a method to reduce the vacuum sublimation by an ion beam process. The density of SiC film deposited by e-beam evaporation method was ∼60% of the density of bulk source material. In this sample, we found that sublimation became appreciable above ∼750 °C under 1.5 × 10−5 torr pressure and the sublimation rate increased with increasing temperature, reaching ∼70 nm/h at 950 °C when the coated sample was heated for 5 h. When the film was irradiated with 70 keV N+ ions prior to heating, the sublimation rate decreased down to ∼23 nm/h at a fluence of 1 × 1017 ions/cm2. However, further increase in fluence beyond this value or extended heating period did not change (decrease or increase) the sublimation rate any more.

► A vacuum sublimation at low temperature occurs on low density SiC film.
► The vacuum sublimation is suppressed by an ion beam bombardment.
► The sublimation rate decreases as increasing the ion fluence.
► Ion fluence beyond a certain value does not change the sublimation rate any further.