The Study of Ti-Doped Gd2O3 Dielectric as Sensing

• Main Authors: Chuan Yu Huang, 黃詮祐
• Other Authors: C. H. Kao
• Format: Others
• Published: 2011
• Online Access: http://ndltd.ncl.edu.tw/handle/87616001215410314626

碩士 === 長庚大學 === 電子工程學系 === 99 === Various high dielectric constant (high-k) materials replacing the gate SiO2 oxide layer have been widely investigated owing to their high dielectric constant and large conduction band offset. In this work, the comparison between the high-k Gd2O3 and Ti-doped Gd2O3 dielectrics by reactive radio frequency (RF) sputtering on single crystalline and polycrystalline silicon were investigated and exploited to characterize the dielectric performance so that we can find the optimal condition to obtain the dielectrics with superior dielectric strength and lower leakage current. Then, the developed Ti-doped Gd2O3 dielectric as sensing membrane was deposited on silicon substrate to apply in the Electrolyte-Insulator- Semiconductor (EIS) device for pH detection. The device performance was improved with proper post-annealing RTA treatment. It can be found that the Ti-doped Gd2O3 membrane annealed at 8000C could achieve high sensitivity of 55.17 mV/ pH, high linearity of 99.99%, low hysteresis voltage of 3.6 mV, and low drift ratio of 1.37 mV/ hr due to reinforcements of crystalline structures. Finally, the above Ti-doped Gd2O3 dielectric as pH sensing membrane on polysilicon combined with proper post deposition annealing for the extended-gate field-effect transistor (EGFET) application at the first time. It also can be found that the high-k Ti-doped Gd2O3 membrane annealed at 8000C could obtain excellent sensing performances. The high-k Ti-doped Gd2O3 sensing membrane shows great promise for future bio-medical device applications.