Quantitative measurement of local carrier concentration of semiconductor from displacement current-voltage curve using a scanning vibrating tip
A new scanning probe method for evaluating the local carrier concentration of semiconductors is presented. The distance between a semiconductor surface and a vibrating tip is changed sinusoidally, and is adjusted to as small as a few nm across which tunneling current I{sub T} flows between the semiconductor surface and the vibrating tip. Displacement current I{sub D} due to the change in electric flux from the semiconductor surface to the vibrating tip flows periodically in accordance with the vibration of the tip. I{sub T} also flows when the distance becomes minimum. Both I{sub T} and I{sub D} flow simultaneously when a d.c. tip voltage V is applied, and these two currents are separated by using a two-phase lock-in amplifier. I{sub D}-V curve is analyzed by taking into account two-dimensional electric flux profile under the tip. In the tip voltage range within which majority carriers are accumulated, I{sub D}-V curve is extrapolated by a straight line. On the contrary, the slope of the curve decreases as the tip voltage is reduced from the voltage range of the accumulation, indicating that the majority carriers are depleted at the center of the Si surface. The theoretical I{sub D}-V curves are in good agreement with the measurement in the tip voltage region where the majority carriers are both accumulated and depleted. The local carrier concentration is able to be determined by making the theoretical I{sub D}-V curve fit the experimental results without contacting the semiconductor surface.
- Research Organization:
- Tokyo Inst. of Tech. (JP)
- OSTI ID:
- 20082419
- Resource Relation:
- Conference: 1999 Materials Research Society Fall Meeting, Boston, MA (US), 11/29/1999--11/30/1999; Other Information: PBD: 2000; Related Information: In: Nondestructive methods for materials characterization. Materials Research Society symposium proceedings, Volume 591, by Baaklini, G.Y.; Meyendorf, N.; Matikas, T.E.; Gilmore, R.S. [eds.], 338 pages.
- Country of Publication:
- United States
- Language:
- English
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