Emission and capture characteristics of deep hole trap in n-GaN by optical deep level transient spectroscopy

Emission and capture characteristics of a deep hole trap (H1) in n-GaN Schottky barrier diodes (SBDs) have been investigated by optical deep level transient spectroscopy (ODLTS). Activation energy ( E emi ) and capture cross-section ( σ p ) of H1 are determined to be 0.75 eV and 4.67 × 10 −15 cm 2 , respectively. Distribution of apparent trap concentration in space charge region is demonstrated. Temperature-enhanced emission process is revealed by decrease of emission time constant. Electric-field-boosted trap emission kinetics are analyzed by the Poole−Frenkel emission (PFE) model. In addition, H1 shows point defect capture properties and temperature-enhanced capture kinetics. Taking both hole capture and emission processes into account during laser beam incidence, H1 features a trap concentration of 2.67 × 10 15 cm −3 . The method and obtained results may facilitate understanding of minority carrier trap properties in wide bandgap semiconductor material and can be applied for device reliability assessment.