Integrated RF MEMS inductors on thick silicon oxide layers fabricated using SiDeox process

We present a new technology called SiDeox to fabricate thick silicon oxide layers for applications in RF MEMS devices such as inductors. Photolithography was done on the silicon substrate with 2 μm patterns. Deep reactive ion etching (DRIE) was performed to form 20 μm deep trenches in the silicon substrate. The DRIE etched silicon wafer was then thermally oxidized in a furnace. Silicon beams with a width of 2 μm were totally oxidized and 2 μm trenches were fully filled with the silicon oxide. Thick silicon oxide layers as thick as 20 μm were fabricated. There is a great potential to build RF devices on such thick silicon oxide layers as substrate to reduce electric losses. Thin film RF inductors were studied, simulated and fabricated using this technology. Electromagnetic simulation shows that the quality factor of such inductors and their self-resonant frequencies are largely improved.