Diamond film-based particle detectors

摘要

Diamond films grown by microwave plasma enhanced chemical vapor deposition have beeninvestigated as particle detectors for nuclear physics. A CH{sub}4-CO{sub}2 gas mixture was usedas gas feed during the growth process. The film morphology, preferential orientation and crystalquality were systematically changed by varying the deposition parameters. In particular, the substratetemperature, T{sub}s, and the CH{sub}4 concentration in the gas mixture were chosen in the 750-850℃ and 47-50% ranges, respectively. The resulting films were characterized by X-ray diffractionand scanning electron microscopy. The correlation of the above structural properties with the response of the diamond-baseddetectors was then extensively studied. To this purpose, they were irradiated with a 5.5MeV{sup}(241)Am alpha particle source under different applied electric fields and their collectionlengths and efficiencies were compared. In particular, it was found that the limiting factor in thedetector performances is related to intra-grain trapping centers, whose effectiveness is increasinglyhigher when the sample preferential orientation tends to (100) texturing or moving away from theSi-diamond interface.