Noise in piezoresistive atomic force microscopy

2019-06-16 18:46:59

device noise force deflection cantilever

责任者: Hansen, Ole;Boisen, Anja 单位: Mikroelektronik Centret, Lyngby, Den 来源出处: Nanotechnology,1999,10(1):51-60 摘要: The noise performance of piezoresistive atomic force microscopy (AFM) devices is investigated. The total deflection noise of a piezoresistive AFM device comprises vibrational noise from the cantilever, and Johnson and flicker noise from the piezoresistor. The vibrational deflection noise is found to have a minimum when the length of the piezoresistor is 2/3 of the cantilever length. The minimum vibrational deflection noise is (9/8 kBT/K)½ for a free cantilever, whereas a supported cantilever has a minimum vibrational noise of (1/8 kBT/K)½ where K is the spring constant of the device. Taking self-heating of the device into account, it is shown that an optimum power level exists at which the total equivalent displacement noise of a device is minimized. This minimum deflection noise is, for a fixed value of the spring constant, approximately proportional to the cantilever thickness, whereas it varies rather slowly with the length of the piezoresistor. 关键词: Nanotechnology;Atomic force microscopy;Piezoelectricity;Vibrations (mechanical);Resistors;Spurious signal noise;Piezoresistive atomic force microscopy;Piezoresistors