Characterization of magnetic materials using a scanning microwave microprobe

Melikyan, Harutyun; Hovsepyan, Artur; Sargsyan, Tigran; Yoon, Youngwoon; Yoo, Hyungun; Babajanyan, Arsen; Lee, Kiejin

doi:10.1016/j.ultramic.2008.04.010

Cited by 6 publications

(1 citation statement)

References 11 publications

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“…Crucially, lifting the tip allows defining a reference zero-signal level that is independent of the sample material, making possible to determine absolute capacitance values in the sample. 5,24 In the capacitance calibration in Sec. III B, the use of the signal from the dielectric material instead of the lifted-tip signal level introduces an error of Ͻ20 aF ͑corresponding to the tip-dielectric capacitance for the 10 nm thick dielectric͒.…”

Section: Afm-tip Capacitance and Effective Tip Radiusmentioning

confidence: 99%

Calibrated nanoscale capacitance measurements using a scanning microwave microscope

Huber¹,

Moertelmaier

Wallis

et al. 2010

Review of Scientific Instruments

132

105

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A scanning microwave microscope (SMM) for spatially resolved capacitance measurements in the attofarad-to-femtofarad regime is presented. The system is based on the combination of an atomic force microscope (AFM) and a performance network analyzer (PNA). For the determination of absolute capacitance values from PNA reflection amplitudes, a calibration sample of conductive gold pads of various sizes on a SiO(2) staircase structure was used. The thickness of the dielectric SiO(2) staircase ranged from 10 to 200 nm. The quantitative capacitance values determined from the PNA reflection amplitude were compared to control measurements using an external capacitance bridge. Depending on the area of the gold top electrode and the SiO(2) step height, the corresponding capacitance values, as measured with the SMM, ranged from 0.1 to 22 fF at a noise level of ~2 aF and a relative accuracy of 20%. The sample capacitance could be modeled to a good degree as idealized parallel plates with the SiO(2) dielectric sandwiched in between. The cantilever/sample stray capacitance was measured by lifting the tip away from the surface. By bringing the AFM tip into direct contact with the SiO(2) staircase structure, the electrical footprint of the tip was determined, resulting in an effective tip radius of ~60 nm and a tip-sample capacitance of ~20 aF at the smallest dielectric thickness.

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Section: Afm-tip Capacitance and Effective Tip Radiusmentioning

confidence: 99%