54-1: Parallel Fabrication for Integration of Electronic and Microelectromechanical Systems

Abstract

We have developed a four mask top gate a-Si:H based process that allows for the parallel production of TFTs, Schottky diodes and surface MEMS elements on large area glass substrates. Simple electronical and micromechanical devices as well as a complex active matrix driven MEMS display demonstrator have been produced for process verification. Furthermore, the process seems to be feasible for applications like ultrasonic transducers or energy harvesting.

39‐4: TFT Integrated Microelectromechanical Shutter for Display Application

“…The top gate TFTs fabricated alongside the MEMS shutters share the same electrical characteristics discussed in [4]. The top gate a-Si:H TFTs are comparable to their industry standard bottom gate counterparts with the measured charge carrier mobility Figure 5 shows the output characteristic curves of a top gate a-Si:H TFT with W/L=20/5.…”

“…A detailed description of the fabrication process has been presented in [4] and is out of the scope of this paper. The process starts with deposition of a buffering layer of silane based PECVD silicon oxide layer on a Corning Eagle XG glass substrate followed by the deposition (sputter) and structuring of the first metal layer.…”

“…~ +368 MPa; compressive stressed nitride: ~ -161 MPa [4]). The top electrode metal properties and thickness also affect the radius of curvature of the released structures.…”

“…Several attempts have been made to produce reflective [1] and transmissive displays [2], [3] utilizing standard display manufacturing technology, but failed to commercialize the products. More recently, our group demonstrated a top gate a-Si:H TFT integrated MEMS process which requires only four masks and has the same complexity of conventional AMLCD or AMOLED backplane processes [4]. The process is based on prestressed structures to achieve necessary out-of-plane actuation range after release.…”

Review of microshutters for switchable glass

“…[19][20][21] Several groups have worked on various versions of microshutters, namely NRC, 17 New Visual Media Group (NVMG), 22,23 University of Kassel, 24,25 Institut National d'Optique (INO), 26 University of Tokyo, 27 Samsung, 28 U.S. Air Force (USAF), 29 Korea Advanced Institute of Science and Technology (KAIST), 30,31 Microelectronic Center of North Carolina (MCNC), 32 Fiat, 33,34 and University of Stuttgart. 35 These groups used various versions of curling electrodes actuated by electrostatic forces for switchable glass applications (window, display, imaging, eyewear, etc.). Other groups have studied the use of curling electrodes for microfluidics, 36 interconnects, 37 and energy storage.…”