A Novel Pd/Pt/High-K dielectric/n-Silicon MIS Schottky Diode with 3D Nano Rod Structure for Hydrogen Sensing Applications

• Main Authors: Wei-ChenYen, 顏瑋辰
• Other Authors: Yen-Kun Fang
• Format: Others
• Language: zh-TW
• Published: 2012
• Online Access: http://ndltd.ncl.edu.tw/handle/11098908232294988527

碩士 === 國立成功大學 === 微電子工程研究所碩博士班 === 100 === We developed the 3D nano rod structure Al/PdPt/ high-K/n-Si/Al MIS Schottky diode for H2 gas sensing applications. Firstly, the Si nano rods were formed on the n type (100) Si substrates with AgNO3and HF mixed etching solution. Then deposited the intrinsic high-K thin films (diamond、HfO2、TiO2) with HWCVD(Hot-Wire CVD) and sputtering system. Followed by deposition of various metal such as Pd、Pt and Pd/Pt as catalytic layer. In final, the device was completed by evaporation of Al on the top and bottom, respectively as electrode contact. We optimized the 3D hydrogen sensor with the following studies: (a) using different catalytic material Pd、Pt and Pd/Pt, (b) to deposit diamond、HfO2 and TiO2 as intrinsic dielectric layer, (c) comparison of the 3D nano rod structure with the conventional 2D thin film type, and (d) to vary intrinsic dielectric layer thickness. Besides, to get the best quality of diamond as the intrinsic layer, we used Raman, XRD, SEM and AFM, respectively for bond structure measurement, crystallinity analyzing, surface roughness, and morphology inspection. Experimental results show that composite of Pd/Pt has the highest activity to catalytic hydrogen atoms into ions, and suppress the hydrogen blister issue. Besides, the nano rods structure indeed can promote sensitivity from 1350% of the conventional 2D thin film type to 2860%. Furthermore, use of diamond as i-layer achieves the fast response time of 9sec, and the highest sensitivity of 217% respectively for 100ppm H2 ambient with the condition of - 3V, 200oC. In addition, we found the developed 3D MIS diode H2 sensor has no significant sensing action to CO2 and alcohol gases Under 150 oC /100ppm H2 ambient, the developed 3D H2 sensor has the best performances of 202% and 9 sec, respectively for sensitivity of and response time , which are better than the reported Pt/HfON/SiC MIS Schottky diode of 53% and 10.5 sec under same conditions.