Study of High-k/III-V MOS Capacitors

• Main Authors: Sung, Hsien-Ming, 宋先敏
• Other Authors: Chang, Yi
• Format: Others
• Language: en_US
• Published: 2009
• Online Access: http://ndltd.ncl.edu.tw/handle/59642490333001311695

碩士 === 國立交通大學 === 材料科學與工程系所 === 98 === Due to its superior carrier transport capability, III-V based MOS field effect transistor technology has the potential of being used for future high frequency low power application. However, the lack of high quality native oxides has been the obstacle for years. Thanks to high-k dielectric deposition technology improvement, high quality gate dielectrics can now be deposited on III-V material for MOS capacitor studies, which is very important before fabricating III-V MOSFETs. In this thesis, molecular beam epitaxy (MBE) was used to deposit HfO2, Pr6O11, and CeO2 for MOS capacitors study. Good scalability was obtained with equivalent oxide thickness (EOT) equal to 2.9nm on HfO2/InxGa1-xAs/InP MOS capacitors. The inversion behavior was also observed for high indium concentration InxGa1-xAs, the mechanism is discussed in this thesis. Pr6O11 and CeO2, which have very high dielectric constant, were also deposited on InxGa1-xAs for MOS capacitor study. It was found that after replacing HfO2 with Pr6O11, the accumulation capacitance increases owing to the high dielectric constant of Pr6O11. The annealing temperature was characterized to unpin the surface Fermi level. The CeO2/ Pr6O11 gate stack structure was also studied; two step annealing was introduced to improve the accumulation capacitance. The reason of the capacitance increase was also observed by cross-sectional TEM image.