Novel high-Q MEMS curled-plate variable capacitors fabricated in 0.35-μm CMOS technology
Novel high-Q MEMS curled-plate variable capacitors fabricated in 0.35-μm CMOS technology
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DOI：
10.1109/tmtt.2007.914657
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发表时间：
2008-02-01
影响因子：
4.3
通讯作者：
Mansour, Raafat R.
中科院分区：
文献类型：
--
作者：
Bakri-Kassem, Maher;Fouladi, Siamak;Mansour, Raafat R.
两个微机电系统（MEMS）卷曲板可变电容器，建立在0.35 μ m CMOS工艺，提出。所提出的电容器的板被有意地向上卷曲以控制调谐性能。本文还介绍了一种适用于MEMS/CMOS电路的无掩模后处理技术。该技术包括干蚀刻和湿蚀刻步骤，并开发用于在CMOS技术中实现所提出的MEMS可变电容器。利用ANSYS有限元软件对电容器进行了力学模拟，并与实测结果进行了比较。提出了两种新的结构。第一个电容器是一个三态结构，表现出一个测量的调谐范围为460%，在1 GHz的平坦的电容响应，是优于传统的数字电容器的上级。在Ansoft的高频结构模拟器（HFSS）中模拟所提出的电容器，并将提取的电容与1-5 GHz频率范围内的测量电容进行比较。第二个电容器是模拟连续结构，在1 GHz时测量的连续调谐范围为115%，无吸合。在1.5GHz时，测量的品质因数优于300。所提出的卷曲板电容器具有小的面积，并且可以实现以构建片上系统。
Two microelectromechanical systems (MEMS) curled-plate variable capacitors, built in 0.35-mu m CMOS technology, are presented. The plates of the presented capacitors are intentionally curled upward to control the tuning performance. A newly developed maskless post-processing technique that is appropriate for MEMS/CMOS circuits is also presented. This technique consists of dry- and wet-etching steps and is developed to implement the proposed MEMS variable capacitors in CMOS technology. The capacitors are simulated mechanically by using the finite-element method in ANSYS, and the results are compared with the measured results. Two novel structures are presented. The first capacitor is a tri-state structure that exhibits a measured tuning range of 460% at 1 GHz with a flat capacitance response that is superior to that of conventional digital capacitors. The proposed capacitor is simulated in Ansoft's High Frequency Structure Simulator (HFSS) and the capacitance extracted is compared with the measured capacitance over a frequency range of 1-5 GHz. The second capacitor is an analog continuous structure that demonstrates a measured continuous tuning range of 115% at 1 GHz with no pull-in. The measured quality factor is better than 300 at 1.5 GHz. The proposed curled-plate capacitors have a small area and can be realized to build a system-on-chip.