MEMS Based on Thin Ferroelectric Layers

Micro-Electro-Mechanical Systems (MEMS) are devices that display the most intense development in modern microelectronics (Kostsov, 2009). The main challenge of microelectromechanics is the design of unique micromechanical structures for various purposes. This research direction is based on achievements of advanced microelectronic technologies and inherits the basic advantages of electronic microchips: high reliability and reproducilbility of characteristics, low cost, and large scales of applications (Esashi & Ono, 2005). The essence of micromechanics implies that advanced microelectronic technologies, for instance, deep etching of silicon (or silicon-on-insulator (SOI)) make it possible to create integrated circuits (ICs) simultaneously with micromechanical structures with unique parameters (determined by their microscopic or nanoscopic sizes, with the transported mass being 10-4 to 10-18 g) controlled by electronic circuits. The most important feature of MEMS is the precision fabrication of moving elements of mechanical structures (earlier inaccessible in mechanics) and their unification in one technological cycle with controlling and processing electronic elements created on the basis of CMOS technology. MEMS applications include the following areas (Kostsov, 2009): microoptoelectromechanics (displays, adaptive optics, optical microswitches, fastresponse scanners for cornea inspection, diffraction gratings with an electrically tunable step, controlled twoand three-dimensional arrays of micromirrors, etc.); high frequency (HF) devices (HF switches, tunable filters and antennas, phased antenna array, etc.); displacement meters (gyroscopes, highly sensitive twoand three-axial accelerometers with high resolution, which offer principally new possibilities for a large class of electronic devices); sensors of vibrations, pressures, velocities, and mechanical stresses; microphones (there are millions of them in cellular phones). Back in 2004, Intel started to deliver RF frontend assemblies fabricated by the MEMS technology for cellular phones. They integrate approximately 40 passive elements, which allows the producer to save up to two thirds of space in the phone casing; wide range of devices for working with microvolumes of liquids and for applications in biology, biochips, biosensors, chemical testing, creation of a new class of chemical sensors, etc.; microactuators and nanopositioners; microgenerators of energy.