Scanning capacitance microscopy ͑SCM͒ is a doping profile extraction using a nanometric probe as a gate of a metal-oxide-semiconductor ͑MOS͒ structure and measuring the differential capacitance. Thanks to the complete MOS equations, the authors propose in this article a description of the differential capacitance calculation. This analytic presentation is based on the solution of the Poisson-Boltzmann equation in the unidimensional mode in silicon and a decomposition of the probe in elementary rings giving capacitance from the surface probe and silicon. As ͓dC͑V g ͒ / dV g ͔␣͑d⌿ s / dV g ͒, this presentation yields to the importance of the surface band bending ⌿ s at the oxide-semiconductor interface. The dC͑V g ͒ / dV g calculation shows that the contact of the probe with the sample has its main contribution over a few nanometers. Results are discussed to obtain a calibration of a SCM probe available in a large range of doping and voltage and to assess the dC͑V g ͒ / dV g signal after erosion of the probe by successive scans.

No abstract

No abstract

In this paper, a new methodology to compare the robustness of sensor structures employed in radiofrequency design for test (RF DFT) architectures for RF integrated circuits (ICs) is proposed. First, the yield loss and defect level of the test technique is evaluated using a statistical model of the Circuit under Test (obtained through non-parametric statistics and copula theory). Then, by carrying out the dispersion analysis of the sensor architecture, a figure of merit is established. This methodology reduces the number of iterations in the design flow of RF DFT sensors and makes it possible to evaluate process dispersion. The case study is a SiGe:C BiCMOS LNA tested by a single-probe measurement.