Performance of the Yb/La2O3/Yb varactor microwave resonators

Abstract In this work a 50 nm thick Yb/ La2O3/Yb varactor device is fabricated and characterized by means of by means of current (I) - Voltage (V) characteristics and 1M- 1GHz impedance spectroscopy. The room temperature analysis of the current voltage characteristics assuming the thermionic current transport mechanism of Shottcky -Ridchardson revealed a dominant effect of the series resistance of the device during the DC conduction. Thus the modified model of Cheung was used to determine the varactor device parameters. The Cheung model revealed a barrier height of ΦB= 0.739 eV and series resistance of Rs= 349.5 K Ω. In addtion, during the forward operation, the device exhibited a low/high current switching property near 3.11 V. On the other hand, when the device was subjected to a propagating AC singnal throught the two Yb terminals it revealed that the impedance of the varicap is dominated by the resistive part in the frequency domain of 10-240 MHz and by the reactive part in the remaining region. The Ac conductance analysis and modeling of the Yb/ La2O3/Yb in accordance with the correlated hopping conduction theory have shown that the electronic conduction is dominated by the hopping jumps over the barrier height. The hopping electron scattering time is estimated from the fitting procedure and found to be 157 ps. With these properties the Yb/ La2O3/Yb varactor device appears to be promising for use in memory applications if subjected to some particular improvements to shift the resonance frequency of the device