Micro and nano-electro-mechanical devices in the cmos back end: relays and resonators

• Autores: Martín Riverola Borreguero
• Directores de la Tesis: Núria Barniol i Beumala (dir. tes.)
• Lectura: En la Universitat Autònoma de Barcelona ( España ) en 2017
• Idioma: inglés
• Tribunal Calificador de la Tesis: Jaume Esteve Tintó (presid.), Jaume Verd Martorell (secret.), Manuel Domínguez Pumar (voc.)
• Programa de doctorado: Programa de Doctorado en Ingeniería Electrónica y de Telecomunicación por la Universidad Autónoma de Barcelona
• Materias:
  • Física
    • Electrónica
  • Ciencias tecnológicas
    • Tecnología de las telecomunicaciones
• Enlaces
  • Tesis en acceso abierto en: TDX
• Resumen

  • Recently, several new emerging devices are starting to be explored because the traditional down-scaling approach of the complementary metal-oxide-semiconductor (CMOS) technology (often called "More Moore") is reaching fundamental limits; mainly due to non-zero transistor off-state leakage. This brand-new domain that goes beyond the boundaries of Moore’s law is commonly named "More than Moore" and is driving interest in new devices for information processing and memory, new technologies for heterogeneous integration of multiple functions, and new paradigms for system architecture. One of these new promising technologies for logic and information processing is the micro- and nanoelectromechanical (M/NEM) relay technology, because of its immeasurably low off-state leakage current and super-steep switching behavior.

    This dissertation proposes to explore the possibilities of leveraging the available layers of the commercial CMOS technology AMS 0.35 µm to implement M/NEM relays. Specifically, two different approaches are explored: in-plane actuated relays defined using solely the via layer, and torsional actuated relays formed with metal and via layers (usually named composite) while supported by vias. Both approaches are supported by the tungsten VIA3 layer, which includes key features such as high hardness, high melting point, low stress and resistance to hydrofluoric (HF) acid, since the mechanical structures are released in a maskless post-CMOS process based on a wet HF enchant.

    Based on the key structural features that the developed relays showed, MEMS resonators based on the VIA3 platform were also fabricated. In this thesis, we also present a particular contribution involving the design and characterization of a dual-frequency oscillator that consist of such reliable torsional tungsten resonators and a high gain, low power and ultra-compact transimpedance amplifier (TIA).

    Finally and parallel to the main thread of this dissertation, RF MEMS switched capacitors are developed as a result of the collaboration through a research contract with the semiconductor manufacturing enterprise SilTerra Malaysia Sdn. Bhd. These devices has the particularity of being fully integrated into the process flow of a low cost, commercial 180 nm CMOS technology (using the SilTerra MEMS-on-CMOS process platform).