Electron stimulated desorption from oxygenated and hydrogenated synthetic diamond films

Thin polycrystalline B-doped diamond films on Si, prepared by microwave plasma chemical vapour deposition, were diagnosed by means of secondary electron emission measurements. Investigations, including caesium deposition, were carried out on a hydrogen and an oxygen-terminated sample cut from the same wafer. Caesiation resulted in a mean secondary electron emission factor <d > at a primary electron energy E_p= 1800 eV equal to 76 and 63 on the H- and O-terminated sample, respectively. Due to electron stimulated desorption, the secondary emission decreased to <d>»45 on both samples under irradiation to a level of ~1 C/cm². On the caesiated samples the reduction of d^* with electron dose was not local, but occurred over the whole surface because of the diffusion of Cs to the irradiated spot.