Monolithic VCOs with High Q MEMS Inductors for RF Applications (Devices:先端デバイスの基礎と応用に関するアジアワークショップ)

概要

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We have developed high Q spiral inductors that make use of MEMS (MicroElectroMechanicalSystems) technology and fabricated VCOs (Voltage Controlled Oscillators) for Wireless LAN applications. The high Q-value of spiral inductors was achieved by air-suspended and thick copper metal electroplated structures. The fabricated spiral inductors were suspended 20 jm over the substrate to reduce the substrate coupling loss and have thick metal layers (〜10 μm) to reduce ohmic loss. The measured Q-value of spiral inductors is over 20 at several GHz for the silicon substrate. Fully integrated 2.4 GHz CMOS VCOs were fabricated by monolithically integrating these MEMS high Q inductors on the top of the CMOS active circuits realized by the Hynix 0.18 μM CMOS process. As post-CMOS process, the MEMS fabrication processes were performed at low temperature below 150℃. The phase noise of VCOs with integrated MEMS inductors is 93.5dBc/Hz at 100kHz of offset frequency and this phase noise value of VCOs with MEMS inductors is improved approximately 60% compared to that of VCOs with CMOS inductors. The 5GHz SiGe VCOs have been designed and are being fabricated by IBM SiGe process, which will be monolithically integrated with MEMS high Q inductors.
社団法人電子情報通信学会の論文
2003-06-24