Development of reflection-type low-power amplifier MMICs using InP-based resonant tunneling diodes

Abstract

Low-power monolithic amplifiers are a critical building block in short-range wireless sensor systems for patient monitoring, implanted biomedical, and radio frequency identification applications. For wireless sensor networks, ultra-low dc-power consumption is a key design issue because of the limited capacity of the small-size battery power source. By utilizing a variety of low-power design techniques, low dc-power consumption in the deep milli-watt range has been attained in conventional transistor-based amplifiers. In order to reduce the power dissipation significantly to sub-mW levels, a reflection-type amplifying topology using negative differential resistance (NDR) devices can be employed. In this thesis, reflection-type low power quantum-effect amplifiers using resonant-tunneling diodes (RTDs) have been for the first time designed and implemented based on an InP-based MMIC technology. Compared to the conventional-type amplifiers, the fabricated RTD amplifiers have shown ultra-low dc-power consumption property with a high figure of merit (FOM) of the gain-to-dc power consumption ratio due to the inherent NDR characteristics of the high-speed InP-based RTD. For the developed InP-based RTD MMIC technology, representative characteristics of the fabricated active and passive devices are as follows. The RTD shows a peak voltage of 0.28 V and a peak current of $60 kA/cm^2$ with a peak-to-valley current ratio (PVCR) of more than 11. The cutoff frequency of the RTD was 77 GHz. The PVCR obtained by the optimized wet-chemical etching process is relatively high at sub-mA peak current levels, compared to previously reported results of the InAs-subwell RTDs. As for passive devices, the spiral inductors, MIM capacitors, and thin film resistors have been implemented for realizing the high-performance quadrature hybrid couplers, which are to be monolithically integrated in the RTD-based low-power amplifier. The hybrid coupler with an impedance transformation ratio of 8...