POWER SATURATION AND THE EFFECT OF ARGON ON THE ELECTRON-SPIN-RESONANCE OF DIAMOND DEPOSITED FROM A MICROWAVE PLASMA

Electron spin resonance (ESR) of microwave plasma chemical vapor deposition diamond shows peaks associated with (i) a P1 substitutional nitrogen defect center, (ii) spin-spin interactions between the paramagnetic sites and neighboring protons, and (iii) a possible contribution from graphitic impurities or amorphous carbon. The P1 spectrum saturates at powers of the order of a few microwatts in contrast to other spectral components which do not display significant saturation. As a result, caution must be exercised when using ESR as a quantitative measure of diamond quality. Films grown from a gas mixture which includes argon do not show the P1 structure or its associated saturation effects. Instead, argon appears to etch or exclude nitrogen from the film leaving carbon-based radicals as the main paramagnetic species in the material. © 1994 American Institute of Physics.