PSPICE analysis of a scanning capacitance microscope sensor

Abstract

A detailed analysis of the capacitance sensor from a scanning capacitance microscope (SCM) is presented. PSPICE circuit simulations are compared with experimental results. The general behavior of the SCM sensor and practical aspects of the sensor-tuning curve are described. It is found that stray capacitances of the magnitude encountered in a conventional SCM measurement configuration are large enough to significantly decrease measurement sensitivity and sensor high-frequency voltage across the tip sample. We have also calculated and measured the delocalized dC/dV caused by stray capacitance, revealing that this background dC/dV must be accounted for in order to obtain the true localized dC/dV.

Dopant loss of ultrashallow junction by wet chemical cleaning

“…7 Figure 3 shows the sheet resistances at 49 points with one-time ͑circles͒ and five-time ͑square͒ SC1s at the different implantation energies. Here, bare wafers were implanted with arsenic at different energies with the dose of 3 ϫ 10 15 /cm 2 , followed by SC1 cleanings of different times.…”

Characterization of thickness variations of thin dielectric layers at the nanoscale using scanning capacitance microscopy

“…The capacitance of the local MIS structure formed by the conductive tip, the dielectric layer, and the semiconductor ͑C tip ͒ has a maximum value typically in the range of 10-40 aF. 13 However, the SCM signal is affected by stray capacitance ͑C stray ͒ between the surface of the sample and the sensing probe ͑cantilever and body͒. [13][14][15][16] C stray strongly disturbs or even dominates the signal under investigation.…”

“…13 However, the SCM signal is affected by stray capacitance ͑C stray ͒ between the surface of the sample and the sensing probe ͑cantilever and body͒. [13][14][15][16] C stray strongly disturbs or even dominates the signal under investigation. In fact, C stray is typically in the range of 0.2 pF but strongly varies with the lateral and vertical probe positions 13 and may achieve values larger than 1 pF.…”

“…[13][14][15][16] C stray strongly disturbs or even dominates the signal under investigation. In fact, C stray is typically in the range of 0.2 pF but strongly varies with the lateral and vertical probe positions 13 and may achieve values larger than 1 pF. 16 This influences the intensity of the SCM output signal, affects the capacitance sensor sensitivity, and hampers the quantitative evaluation when measurements are performed on locations relatively far from each another.…”

“…16 This influences the intensity of the SCM output signal, affects the capacitance sensor sensitivity, and hampers the quantitative evaluation when measurements are performed on locations relatively far from each another. 13 Therefore, quantitative interpretation of SCM results is challenging and often not very meaningful even in the presence of calibration data.…”