Highly rectifying contacts on (In,Ga) 2 O 3 thin films grown by PLD

The fabrication of rectifying contacts is essential in order to realize active devices like diodes, field-effect transistors and photodetectors. In this contribution, properties of Schottky barrier and pn-heterojunction diodes on heteroepitaxial $\beta$ -Ga 2 O 3 and $\alpha$ -In 2 O 3 thin films grown by pulsed laser deposition are discussed. Additionally, the properties of such rectifying contacts on ternary (In,Ga) 2 O 3 thin films having a lateral composition gradient are presented. In order to improve rectification and on-resistance of the contacts, functional layers were introduced. By using a comprehensive model, taking into account thermionic emission, thermionic field emission and charging currents as well as certain non-idealities, the thickness and net doping density of these layers were optimized. Further, the model allows fitting entire current-voltage characteristics yielding valuable information on dominant current transport mechanisms and their specific parameters.