Statistical analysis of current–voltage characteristics in Au/Ta 2 O 5 /n-GaN Schottky barrier heterojunction using different methods

We report on the influence of incorporation of Ta 2 O 5 thin film at the interface of Au/GaN by means of e-beam evaporation technique. The fabricated Au/Ta 2 O 5 /n-GaN MIS junctions have been analysed using I–V measurements and were extended to a voltage range of ± 20 V. The Schottky diode parameters for instance Φ bo , n and R S values are evaluated using I–V curves at room temperature. The statistical distribution analysis provides the mean ‘ Φ bo ’ value of 0.85 eV with deviation of 0.00181 eV and mean value from ‘ n ’ is 1.36 with a normal deviation of 0.00562. Two important electrical parameters such as R S and R sh values are also extracted from I–V characteristics. Furthermore, Cheung, Norde, modified Norde, Hernandez and Chattopadhyay methods are used to evaluate the Schottky barrier parameters from I–V data. The comparison is made between the extracted electrical parameters such as n , Φ bo and R S from I–V characteristics of Au/Ta 2 O 5 /n-GaN MIS junctions and are in well agreement with each other. Under forward-bias, the fabricated Au/Ta 2 O 5 /n-GaN MIS junction conduction mechanisms such as ohmic and SCL were found to be dominant at lower and higher voltage regimes, respectively. By fitting reverse-bias region of I–V curves, PF conduction mechanism was found to be dominant at the interfaces of Au/Ta 2 O 5 /n-GaN. In conclusion, the obtained superior rectification ratio of 6.06 × 10 4 and higher SBH of 0.87 eV was ascribed to the purposefully deposited undoped GaN buffer layer between epitaxial GaN and sapphire substrate.