Papers by Author: J. Supadech

Abstract: Two different viscous coating materials, which are Polydimethylsiloxane (PDMS) mixed with 10%wt of Dicumylperoxide (DCP), and Semifluorinate Silane (SFS), were applied to silicon micro-asperity. The cosine’s Young and viscosity of those coating materials are -0.3584,-0.3496 and 3.176x10-3, 1.339 x10-3 Pas, respectively. The rough surfaces with nine asperity shapes were studied. The results shown that, pillar shape has an effect on water contact angle (WCA): Stripe asperity cannot make the average WCA greater than 150. When consider the pillar asperity, the WCA falls between 152 and 157, which exhibits a superhydrophobic surface property. However, actual WCA of the micro-asperity coated with PDMS+10%wt of DCP is lower than that coated with SFS around 1 to 7. High viscous material makes the asperity size bigger than the design and decreases the WCA: the low viscous material is more suitable for coating on the asperities.

Abstract: In this study, we demonstrate the disposable polydimethylsiloxane (PDMS) microchip provided for DNA amplification. The device consists of two main parts. The first part is PDMS/glass stationary chamber, the other part is a temperature-control microdevice on SiO2/Si substrate. This device consists of a thin film Pt-microheater and a Pt-temperature sensor, which were fabricated with CMOS compatible process. The performance of the device in the DNA amplification shows that, with 10 μl of PCR mixture volume, the approximately 700 bp DNA were successfully amplified within 50 minutes by 30 PCR cycles. The amplified products were comparable with those of a conventional method using electrophoresis. The PCR chip is also suitable for mass production.

Abstract: This paper presents the relation between the staring cobalt thickness with carrier generation lifetime, which effects to the sensitivity of p-n junction temperature sensor. The starting cobalt thickness of 12, 20 and 30nm have been used. The carrier generation lifetimes have been calculated from the reverse current-voltage (I-V) characteristics. The highest carrier generation lifetime has been obtained in the case of 12nm starting cobalt thickness. The highest sensitivity of p-n junction temperature sensor has also been observed from the case of 12nm starting cobalt thickness. The sensitivity has been calculated from the relation between leakage current versus temperature. The sensitivity of p-n junction temperature sensor can be improved by increasing carrier generation lifetime.