Imaging of charge transport in polycrystalline diamond using ion-beam-induced charge microscopy

Studies have been made using a 1 μm spatial resolution ion-beam-induced charge (IBIC) technique of the charge transport distribution in polycrystalline diamond produced by chemical vapor deposition. The devices tested used a coplanar electrode structure fabricated only on the growth side of the diamond film, and were predominantly sensitive to charge transport close to the growth surface of the diamond film where the diamond crystallites are largest. Irradiation with 5.48 MeV alpha particles gave a pulse height spectrum with a broad full energy peak and a mean charge collection efficiency of 15%. IBIC images obtained using microfocus proton and alpha particle beams showed spatially resolved regions of high charge collection efficiency correlating to individual diamond crystallites with a typical width of 20 μm, as observed by secondary electron microscopy.