Accurate determination of ultrathin gate oxide thickness and effective polysilicon doping of CMOS devices
- 1 December 1997
- journal article
- Published by Institute of Electrical and Electronics Engineers (IEEE) in IEEE Electron Device Letters
- Vol. 18 (12) , 580-582
- https://doi.org/10.1109/55.644077
Abstract
We present an efficient and accurate method to characterize the physical thickness of ultrathin gate oxides (down to 25 ˚ A) and the effective polysilicon doping of advanced CMOS devices. The method is based on the model for Fowler-Nordheim (F-N) tunneling current across the gate oxide with correction in gate voltage to account for the polysilicon-gate depletion. By fitting the model to measured data, both the gate oxide thickness and the effective poly doping are unambiguously determined. Unlike the traditional capacitance-voltage ( ) technique that overestimates thin-oxide thickness and requires large area ca- pacitor, this approach results in true physical thickness and the measurement can be performed on a standard sub-half micron transistor. The method is suitable for oxide thickness monitoring in manufacturing environments.Keywords
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