Application of Chemical Oxidation in Nitric Acid and Anodic Oxidation Compensation Techniques on Preparing Nano-Scale High-k HfO2 Gate Dielectrics in MOS Devices
Date Issued
2005
Date
2005
Author(s)
Chang, Chia-Hua
DOI
en-US
Abstract
In this work, a method of cost-effective and room temperature process for preparing high-k hafnium oxide gate dielectrics is proposed. The alternative high dielectric constant gate dielectrics had been widely investigated because of their thicker physical thickness that can reduce the leakage currents under the same equivalent oxide thickness (EOT). HfO2 is a potential gate insulator for future CMOS applications due to its high dielectric constant as compared to Si3N4 and Al2O3 as well as their high free reaction energy with silicon. In our research, HfO2 was prepared by chemical oxidizing of thin hafnium films in nitric acid and then followed by rapid thermal anneal (RTA). They exhibited good performance in uniformity and electrical characteristics. The optimal parameters of HNO3 oxidation including acid concentration, dipped time, the effects of post-oxidation anneal (POA), and post-metallization anneal (PMA) are studied by the leakage current, interfacial properties, and stress reliability. The technique of oxidation followed by anodization compensation was also investigated. Though the gate dielectrics prepared by the aforementioned method shows excellent properties, the electrical characteristics of smaller leakage current, higher breakdown field, and excellent reliability were observed by introducing the room temperature anodization compensation technique. The proposed method is of value for high-k gate dielectric engineering.
Subjects
氧化鉿
金氧半電容元件
陽極氧化補償技術
High-k gate dielectrics
HfO2
MOS capacitors
Anodic oxidation compensation techniques
Type
thesis
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