Enhanced electron emission from diamond film deposited on pre-seeded Si substrate with nanosized diamond power

Diamond film was synthesized by microwave plasma chemical vapor deposition (MWPCVD) method. The deposition process of diamond film on 4-in. pre-seeded mirror polished silicon wafer was divided into four steps: (a) seeding nano-diamond powder on Si surface; (b) annealing for increasing the adsorbed strength between diamond powder and substrate; (c) diamond film growth; (d) bombarding with H+ ion for decreasing film stress and obtaining planar field emission from diamond film with large area. Scanning electron microscopy (SEM), Raman spectroscopy and stress measurement system were used to characterize the structure and property of diamond film. The electron emission from large area diamond film on seeded substrate was described and compared with that from diamond film deposited on Si substrate scratched by diamond powder. The results suggested that low-field electron emission and high emission current could be obtained from diamond film deposited on seeded substrate due to the reduction of interface energy barrier for electron tunneling. A threshold field of 3.0 V/mm and emission current density of 1 mA/cm2 at 30 V/mm were achieved.