Low Power Tunneling Current Strain Sensor Using MOS Capacitors

Abstract

Although microelectromechanical systems (MEMS) strain sensors have been widely researched and commercialized for decades, the increasing requirement for low power sensors is motivating research on new techniques. We present a new technology to make very low power sensors by measuring the tunneling current through a MOS capacitor. The tunneling current can be in the nanoamp range, which is a good alternative for low power sensing. We demonstrate a power consumption of a couple of nano-Watts with a minimum detectable strain of 0.00036%. The fabrication process is very simple and compatible with CMOS processes. We find that noise is lower in inversion region, and therefore, it is better to bias device to inversion region. To study the sensitivity in the inversion region, a model was developed to compute the strained tunneling current comprised of electron conduction band tunneling current and electron valence band tunneling current. The model fits our experiment very well.[2014-0127]

A Method of Precise Auto-Calibration in a Micro-Electro-Mechanical System Accelerometer

“…The high nonlinearity between the tunneling current and the displacement [ 39 ] is a huge problem when employed as the basic acceleration-sensing principle. Nevertheless, there are many examples in which a tunneling current transducer, employing a tunneling current passing through the air gap between the tip and the plate [ 40 ], has been applied in the structure of a MEMS accelerometer, as presented, e.g., in [ 41 , 42 , 43 , 44 ]. A typical solution to this nonlinearity is usually the operation of the accelerometer with force feedback [ 45 ].…”

“…However, in the case of the proposed detectors, this nonlinearity is a significant advantage since it ensures an extremely high sensitivity over a very limited displacement range [ 40 ]. Moreover, an accurate and stable tunneling current transducer is not required, since the specific position can be determined on the basis of the peak of the recorded tunneling current regardless of its absolute value.…”

Capacitance Analysis of Transient Behavior Improved Metal-Insulator-Semiconductor Tunnel Diodes With Ultra Thin Metal Surrounded Gate

“…T HE devices with ultra thin dielectric become more important as the continuous scaling of the modern integrated circuit fabrication. The metal-insulator-semiconductor (MIS) tunnel diodes has already shown their application, such as temperature and strain sensors [1], [2], photodetector [3] and solar cells as well [4]. At the same time, thanks for the ultra thin dielectric, MIS tunnel diodes have a good ability to store more charges as capacitors.…”

Piezo-tunneling strain sensors integrated on plastic by combining vacuum thin film coatings and 3D printing technologies

“…They can also be used in the field of robotics, aerospace engineering and transportation to develop lightweight plastic Micro-Electro-Mechanical Systems (MEMS) that can be conformably integrated on non-planar surfaces (Xiao 2008). Among the different approaches which have been proposed in literature these past few years, piezo-tunneling strain sensors give rise to gauge factors in the range of 10 to 300 which compete with that of monocrystalline silicon (standard for piezoresisitive MEMS) (Herrmann 2007;Schlike 2016;Jiang 2015;Zhu 2015;. The principle of piezo-tunneling strain sensor is based on the fact that the electrical resistance of a tunnel junction exponentially varies with its parameters (junction length, electron effective mass, barrier height).…”

“…This concept has been first exploited with metallic nanoparticle assemblies in which the current is flowing by tunnel effect from nanoparticle to nanoparticle (Herrmann 2007;Schlike 2016;Jiang 2015;. This concept has been later used to advantage with single MOS (Metal Oxide Semiconductor) junctions (Zhu 2015) and more recently by our group with MOM (Metal Oxide Metal) junctions . The key advantage of MOM junctions as compared to MOS junctions is attributed to their elaboration process which requires a low thermal budget and which can be applied on a variety of substrates (e.g.…”