An innovative NEMS pressure sensor approach based on heterostructure nanowire

Mechanical stress is increasingly applied in microelectronics. For instance, strained silicon technology is widely used to improve carrier mobility and then driver current for advanced MOS transistors. For micro-electromechanical systems, piezoresistive effects are universally employed in pressure sensors. In this paper, we present an original method for studying mechanical stress impact on the property of nano-devices placed on ultra-thin membranes, which has several advantages compare with the conventional four-point-bending method. Using this architecture, we have studied an innovative Nano electromechanical system (NEMS) pressure sensor to investigate its property in static and dynamic modes respectively. We have determined the optimal orientation and position of a nanowire on the membrane. We simulated the electrical transport behavior in the hetero-junction nanostructure by interrupting the nanowire with a dielectric adopting tunnel junction approach. We show that a large improvement in pressure measurement sensitivity can be obtained relying on the direct tunneling current. We also investigate the mechanical stress impact on the potential barrier height that leads to the variation of the tunnel current and dynamic multi-bends of this nanostructure in its dynamic deformation modes. Finally, our work helps to understand the electrical and mechanical properties of the nanostructure under the influence of large mechanical stress and to design innovative NEMS pressure sensors. (C) 2009 Elsevier B.V. All rights reserved.