Trench Pd/Si metal-oxide-semiconductor Schottky barrier diode for a high sensitivity hydrogen gas sensor

Abstract

The structure and hydrogen gas sensing properties of a trench Pd-thin oxide-Si Schottky diode are studied and compared with a planar one. The trench diode possesses additional vertical surface area and a large number of interface traps induced by injected hydrogen ions. The additional vertical surface area enlarges the entrance of H2 molecules, and the generated middle traps enhance the carrier tunneling. Also, the generated shallow traps can catch the carrier to form a thin surface charge layer and lower the barrier. The sensitivity of the trench diode is thus higher than that of the planar diode under room-temperature operation.