A laser patterned zero bias Au/Al2O3/Mo metal-insulator-metal diode rectifier for RF detection

Abstract

Metal-insulator-metal (MIM) diode is considered as a promising candidate for various high frequency applications owing to its tunneling dominant ultra-fast switching time. The zero bias operation of these diode rectifiers is very desirable for detection of low power RF signals. In the present work, an Au/Al2O3/Mo MIM diode integrated with coplanar waveguide (CPW) is fabricated and its rectification response is evaluated at zero bias i.e. without applying any external dc biasing across the diode. The complete device structure was patterned using the facile direct laser beam lithography technique forming the junction area of diode as small as 1 µm2. The as fabricated diode exhibited maximum sensitivity of 9.4 A/W at zero volt leading to significant zero bias rectification performance. The direct rectification at 5 MHz and 10 MHz were obtained with rectification ratios of 2.33 and 1.57, respectively while at 7 GHz frequency with 0 dBm RF power, the maximum rectified dc current was measured as 7 µA. The zero bias RF to dc conversion efficiency of the device was estimated as 0.55%.