A low‐cost and reliable optical inspection system for rapid surface roughness measurements of polycrystalline thin films

Abstract

Excimer laser crystallization is a well‐known industrially used technique to produce high‐performance polycrystalline silicon thin films on the commercially available inexpensive glass substrates for the development of high‐performance low temperature polycrystalline silicon thin‐film transistors in active matrix flat panel displays. A rapid optical measurement system for rapid surface roughness measurement of polycrystalline silicon thin films was developed in this study. Two kinds of thicknesses of polycrystalline silicon thin films were used to study rapid surface roughness measurements. Six different incident angles were employed for measuring surface roughness of polycrystalline silicon thin films. The results reveal that the incident angle of 20° was found to be a good candidate for measuring surface roughness of polycrystalline silicon thin films. Surface roughness (y) of polycrystalline silicon thin films can be determined rapidly from the average value of reflected direct current voltage (x) measured by the optical system developed using the trend equation of y = –8.9854x + 91.496. The maximum measurement error rate of the optical measurement system developed was less than 5.72%. The savings in measurement time was up to 83%.

A reliable approach to a rapid calculation of the grain size of polycrystalline thin films after excimer laser crystallization

“…Excimer laser crystallization (ELC) is an industrial technique used for preparing poly-Si thin films on commercially available, inexpensive glass substrates for the development of high-performance TFTs in active-matrix flat panel displays. [1][2][3][4][5][6] A rapid deposition of the laser-energy density, on a nanosecond time scale, onto the surface region of the an amorphous-silicon (a-Si) thin film leads to its melting and recrystallisation into a poly-Si thin film, while keeping the glass substrate at a low temperature. The final quality of the device depends significantly on the phase-transformation mechanisms which need to be manipulated precisely for obtaining poly-Si thin films with a large grain size and a good uniformity.…”