Published online by Cambridge University Press: 17 March 2011
The capacitance detection techniques, applicable to Scanning Capacitance Microscopes, have been analyzed from the point of view of signal-to-noise ratio that finally affects the achievable lateral resolution. It was found that comparable sensitivities can be achieved from relatively low frequencies below 1 MHz up to the GHz region. On conducting surfaces, resolution better than 5 nm has been achieved. It is limited by the minimum probe-to-sample distance, below which large tunneling current would occur. Increasing the applied voltage above a few volts increases the sensitivity at the cost of lateral resolution, since, at high voltage and small probe-sample distance, field emission could occur.