In situ diamond growth rate measurement using emission interferometry

The growth rate of diamond synthesized in an oxygen-acetylene flame has been measured in situ with an infrared pyrometer. During the growth, the sample’s emitted radiation intensity is modulated in time by interference phenomena in the growing diamond film, causing a periodic variation of the pyrometer’s apparent temperature reading. Diamond film growth rates determined from the period of these oscillations agree well with rates derived from the film thickness. This technique is used to determine the variation of diamond growth rate with substrate temperature over the range of 444–1200 °C. An Arrhenius analysis of the data shows two distinct diamond growth regimes.