Improving metal-oxide-metal (MOM) diode performance via the optimization of the oxide layer.

Abstract

Small area metal-oxide-metal (MOM) diodes are being investigated in many research groups for the detection of THz frequency radiation. In order to create a high-speed rectifying device, the central oxide layer of the MOM structure must be thin and have known physical characteristics. The thickness, structure and uniformity of the oxide can be controlled during the fabrication process. In the work presented here, the effects of both oxygen plasma concentration and annealing temperature during fabrication of Ti/TiOₓ/Pt MOM diodes have been explored. It has been found that, by reducing the oxygen gas concentration from previous work, the TiOₓ layer can be more repeatable and uniform. Furthermore, for an anneal temperature up to a threshold temperature in the 200℃ to 250℃ range, the performance of the diodes is excellent, with a value of zero-bias curvature coefficient (CCZB) that can be up to 4.6V⁻¹. For higher temperature treatments, the value of CCZB decreases to a maximum of 2.0V⁻¹. Similar trends in AC tests can be seen for voltage and current responsivity values.