Mapping of polarization and detrapping effects in synthetic single crystal chemical vapor deposited diamond by ion beam induced charge imaging

摘要

Diamond has been regarded as a promising radiation detector material for use as a solid state ionizing chamber for decades. The parameters degrading the charge transport from what is expected from an ideal crystal are still not completely understood. Recently, synthetic chemical vapor deposited (CVD) single crystal diamond has become available, offering the opportunity to study the properties of synthesized material independent of grain boundaries. We have studied the charge transport of a synthetic single crystal diamond with α-particle induced charge transients as a function of temperature and established the presence of a shallow hole trap with an activation energy of 0.29±0.02 eV in some parts of the detector. Ion beam induced charge imaging has been used to study the spatial variations of the charge transport in a synthetic single crystal diamond. Pulses influenced by the shallow hole trap had their origin close to the substrate/CVD interface of the sample. They could be clearly distinguished from pulses affected by reduced charge carrier velocities due to polarization phenomena, which varied systematically with the growth direction of the CVD diamond material.