Deep levels in n-type Schottky and p(+)-n homojunction GaN diodes

The deep level spectra in both p(+)-n homojunction and n-type Schottky GaN diodes are studied by deep level transient spectroscopy (DLTS) in order to compare the role of the junction configuration on the defects found within the n-GaN layer. Both majority and minority carrier DLTS measurements are p erformed on the diodes allowing the observation of both electron and hole t raps in n-GaN. An electron level at E-c-E-t=0.58 and 0.62 V is observed in the p(+)-n and Schottky diodes, respectively, with a concentration of simil ar to3-4x 10(14) cm(-3) and a capture cross section of similar to1-5x10(-15 ) cm(2). The similar Arrhenius behavior indicates that both emissions an re lated to the same defect. The shift in activation energy is correlated to t he electric field enhanced-emission in the p(+)-n diode, where the junction barrier is much larger. The p(+)-n diode configuration allows the observat ion of a hole trap at E-t-E(v)0.87 eV in the n-GaN which is very likely rel ated to the yellow luminescence band.