An Investigation of High Dielectric Constant of RF-sputtered HfO2 Thin Films

• Main Authors: Yeh, Chang-Moun, 葉長茂
• Other Authors: Chen, Shih-Chih
• Format: Others
• Language: zh-TW
• Published: 1997
• Online Access: http://ndltd.ncl.edu.tw/handle/62974981089214242913

碩士 === 國立雲林科技大學 === 電子與資訊工程技術研究所 === 85 === 　　In this thesis, the Hafnium dioxide (HfO2) thin films are deposited on p-Si substrates by the radio-frequency(RF) magnetron sputtering system. The material and electric properties of the deposited HfO2 films before and after annealing process are studied. 　　The crystal condition and depth profile of the HfO2 films are analyzed by the x-ray diffraction patterns (XRDs) and the secondary ion mass spectrometry (SIMS), respectively. It shows that the as-deposited HfO2 film is amorphous and becomes poly-crystalline after 400℃ annealing. A very thin SiO2 layer (about 50A) is found between HfO2 and Si-substrate. 　　In this study the Al/HfO2/Si MIS structure is fabricated. From the C-V and I-V measurements the maximum dielectric constant is obtained about 28 and the low leakage current is obtained about 500nA/cm2 at an applied electric field of 1MV/cm. The Time-Dependent-Dielectric-Breakdown (TDDB) tests are also applied on the MIS structure in this issue to estimate the operation lifetime about 94 years. The dielectric breakdown of HfO2 films is about 40MV/cm. The potential barrier of A1/HfO2 is measured from teh photorespone about 1.15eV. The electron affinity of HfO2 is calculated about 3.1eV. Anyway, the excellent HfO2 insulators with good properties, such as high dielectric constant, low leakage current, well-behaved C-V and I-V characteristics, and good stability, have been fabricated. These characteristics of HfO2 insulators show it is quite promising for ULSIand DRAM applications.