| For general communications systems there is a continuous movement towards smaller and lighter systems with increased performance and functionality, as well as reduced power consumption. These requirements place a considerable demand on the circuit power dissipation, design, and circuit compatibility, which consequently increase the design complexity, manufacturing cost and overall weight of current components and devices. Based on this need, Micro-Electromechanical Systems for RF applications (RF-MEMS) are currently being developed for wireless applications, which will enable the design of new products with enhanced functionality and reduced power consumption. By using silicon surface micromachining techniques combined with flip-chip technology, MEMS devices such as variable capacitors and suspended inductors have been fabricated with excellent performance.; This research also combines the realization of flip-chip devices utilizing a novel fabrication approach of coating released MEMS devices with nanometer-thin films using atomic layer deposition (ALD). The ALD process is capable of depositing a variety of conformal thin-film materials to protect MEMS devices from electrical breakdown, mechanical wear, and stiction failure. For RF-MEMS variable capacitors, a dielectric layer is crucial to the operation of electrostatically-actuated MEMS devices to prevent electrical shorting.; Results obtained for variable RF-MEMS capacitors used in RF circuits demonstrate a great potential for these devices to operate with very low power consumption and equal performance to solid-state devices. |
