Title :
CMOS current amplifier for AFM impedance sensing on chip with ZeptoFarad resolution
Author :
Bianchi, D. ; Carminati, Marco ; Ferrari, Giorgio ; Sampietro, Marco
Author_Institution :
Dipt. di Elettron., Inf. e Bioingegneria, Milan, Italy
Abstract :
A new sensing configuration based on the direct use of the metal input pad of a dedicated CMOS amplifier as a conductive substrate electrode for nanoscale high-performance electrical measurement with a standard conductive AFM is proposed and experimentally validated. Combining the state-of-the-art performance of an integrated current preamplifier (5MHz bandwidth, 14fA/sqrt(Hz) noise at 1MHz) with pad and setup optimization, it has been possible to straightforwardly achieve 14zF total capacitive rms resolution (0.5V applied at 1MHz with 1s averaging time) that corresponds to 75pm resolution in tracking the piezo vertical movement (allowing the detection of 6nm steps of the cantilever with a SNR of ~40dB).
Keywords :
CMOS analogue integrated circuits; HF amplifiers; atomic force microscopy; electric sensing devices; electrodes; integrated circuit measurement; integrated circuit noise; optimisation; preamplifiers; radiofrequency integrated circuits; CMOS current amplifier; ZeptoFarad resolution; bandwidth 5 MHz; cantilever; capacitive rms resolution; conductive substrate electrode; frequency 1 MHz; integrated current preamplifier; metal input pad; nanoscale high-performance electrical measurement; optimization; size 6 nm; standard conductive AFM impedance sensing on chip; voltage 0.5 V; Application specific integrated circuits; Bandwidth; Capacitance; Microscopy; Nanoscale devices; Noise; Substrates; atomic force microscope; impedance; low-noise; nanoscale;
Conference_Titel :
Ph.D. Research in Microelectronics and Electronics (PRIME), 2013 9th Conference on
Conference_Location :
Villach
Print_ISBN :
978-1-4673-4580-4
DOI :
10.1109/PRIME.2013.6603124
