| Zugriffsnummer | 31246 |
| Dokumenttyp | Konferenzartikel in Zeitschrift |
| Sprache | Englisch |
| Titel | A novel pitch evaluation of one-dimensional gratings based on a cross-correlation filter |
| Autor(in); Institution |
Chen, Xiaomei; University of Huddersfield, Centre for Precision Technologies, Huddersfield, UK
Koenders, Ludger; 5.1, Oberflächenmesstechnik, PTB-Braunschweig
|
| Quelle/Jahr | Measurement Science and Technology: 25 (2014), 4, 044007-1 - 044007-9 |
| ISSN | 0957-0233 (PRINT) ; 1361-6501 (ONLINE) |
| DOI | |
| Verlag | Bristol: IOP |
| Konferenzangaben | Nanoscale 2013, Paris, 25-26, April, 2013, France |
| Klassifikationscode | PACS: 84.30.Vn ; PACS: 68.37.Ps ; PACS: 07.50.Qx ; PACS: 68.37.Ef |
| Freie Schlagworte | Pitch evaluation ; Pitch and uniformity measurement ; Cross-correlation ; SPM |
| Zusammenfassung | If one-dimensional (1D), p-period and arbitrarily structured grating position-related topographical signals coexist with noise, it is difficult to evaluate the pitch practically using the center-of-gravity (CG) method. The Fourier-transform-based (FT) method is the most precise to evaluate pitches; nevertheless, it cannot give the uniformity of pitches. If a cross-correlation filter - a half period of sinusoidal waveform sequence (p T period), cross-correlates with the signals, the noise can be eliminated if p T ≈ p. After cross-correlation filtering, the distance between any two adjacent waveform peaks along the direction perpendicular to 1D grating lines is one pitch value. The pitch evaluation based on the cross-correlation filtering together with the detection of the peak’s position is described as the peak detection (PD) method in this paper. The pitch average and uniformity can be calculated by using the PD method. The computer simulation has indicated that the average of pitch deviations from the true pitch and the pitch variations are less than 0.2% and 0.2% for the sinusoidal andrectangular waveform signals with up to 50% uniform white noise, less than 0.1% and 1% for the sinusoidal and rectangular waveform signals and 0.6% and 2.5% for the triangular waveform signal if three waveform signals are mixed with Gaussian white, binomial and Bernoulli noise up to 50% in standard deviation, one probability and trial probability, respectively. As examples, a highly oriented pyrolytic graphite (HOPG) with a 0.246 nm distance between second nearest neighbour atoms and a 1D grating with 3000 nm nominal pitch are measured by a ultra-high vacuum scanning tunneling microscope (UHV STM) and a metrological atomic force microscope (AFM), respectively. After the position-related topographical signals are cross-correlation filtered, the 0.240 and 3004.11 nm pitches calculated by using the PD method are very close to the 0.240 and 3003.34 nm results evaluated by the FT method. |
