A. Garg

Publications (2)0 Total impact

• Source

  Available from: purdue.edu

  Conference Proceeding: Electrostatically tunable analog single crystal silicon fringing-field MEMS varactors

  J. Small, Xiaoguang Liu, A. Garg, D. Peroulis
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  ABSTRACT: This paper reports on the design of a new analog MEMS varactor that uses electrostatic fringing-field actuation and is based on a single-crystal silicon movable structure coated with a thin metallic layer. Electrostatic fringing-field actuation allows for an analog displacement with no pull-in instability that yields a much larger tuning ratio compared to conventional electrostatic designs. In addition, total lack of dielectric layers and the use of single crystal silicon for the moving membrane significantly enhances the robustness of our proposed varactor by making it devoid of dielectric charging and stiction, insensitive to process variations, amenable to high yield manufacturing and less susceptible to hysteresis and creep. Based on this idea, we present example designs and the associated fabrication processes for varactors that exhibit a tuning ratio of 4.5:1 with capacitance values in the range of 43-200 fF achieved with DC voltages of 0-55 V. Such varactors are key elements in MEMS matching networks, tunable filters and reconfigurable antennas in the K/Ka/W-bands.
  Microwave Conference, 2009. APMC 2009. Asia Pacific; 01/2010
• Source

  Available from: purdue.edu

  Conference Proceeding: Impact of sacrificial layer type on thin-film metal residual stress

  A. Garg, J. Small, Xiaoguang Liu, A.K. Mahapatro, D. Peroulis
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  ABSTRACT: In this paper we study the impact of two sacrificial layers on the final residual stress of thin gold films. In particular, we compare a typical photoresist layer (Shipley SC1827) to single-crystalline silicon. We fabricate and measure cantilever beams on both sacrificial layers and study their residual stresses by analyzing the final displacement profile of the released beams. All samples were fabricated at the same time and under identical conditions. The study clearly shows that the induced stress on thin films is dependent on the sacrificial layer. The gold film deposited over the single-crystalline silicon shows nearly zero gradient stress after release. On the other hand, gradient stress dominates the gold film deposited during the same run but over a photoresist layer. Such results are very useful in designing and fabricating a wide variety of low-stress actuators and sensors.
  Sensors, 2009 IEEE; 11/2009