The Fabrication and Characterization of Metal(Al)-Oxide-Si Capacitors and Field-effect Transistors Using Dy2O3 and Sm2O3 Gate Oxide

• Main Authors: Yu-Ren Hwang, 黃郁仁
• Other Authors: Joseph Ya-Min Lee
• Format: Others
• Language: zh-TW
• Published: 2006
• Online Access: http://ndltd.ncl.edu.tw/handle/17705595910958225192

碩士 === 國立清華大學 === 電子工程研究所 === 94 === Abstract Metal-insulator-semiconductor (MIS) capacitors and n-channel Metal-oxide-semiconductor-field-effective-transistors (MOSFETs) with Sm2O3 and Dy2O3 gate dielectrics were fabricated. The electrical conduction mechanism in Sm2O3 thin films was investigated. The surface roughness of the Sm2O3 and Dy2O3 capacitors was measured by atomic force microscope (AFM). The rms roughness values of the Sm2O3 and Dy2O3 thin films at rapid-thermal-annealed at 500℃ are 1.92 nm and 1.1 nm with an oxide thickness of 19nm. After removing the Sm2O3 and Dy2O3 films surface roughness of silicon is in the range from 0.3~0.5nm. It was found that Schottky emission was the dominating conduction mechanism in the electrical field from 0.08 to 0.81 MV/cm in the temperature range from 325K to 500K. Fowler-Nordheim tunneling is the dominating conduction mechanism at the electrical field above 0.9 MV/cm at 77K. The Al/Sm2O3 barrier height and the effective electronic mass calculated from these two conduction mechanisms using an iteration method are 0.82 eV and 0.13 mo, respectively. The MOSFETs with Sm2O3 and the Dy2O3 gate dielectric layers show normal IDS-VDS and IDS-VGS characteristics. The effective electron mobility was measured by the split C-V method. The values of the mobility of MOSFETs with Sm2O3 and Dy2O3 gate dielectric are 211 and 251 cm2/V-s, respectively. The dependence of the threshold voltage on temperature for n-channel MOSFETs with Sm2O3 and Dy2O3 gate dielectric was also measured. The δVT/δT values are -4.71 mV/K and -3.45mV/K for n-channel MOSFETs with Sm2O3 and the Dy2O3 gate dielectrics, respectively.