AVS 53rd International Symposium
    Electronic Materials and Processing Thursday Sessions
       Session EM-ThP

Paper EM-ThP38
Characteristics of the Laminated HfO@sub2@/Al@sub2@O@sub3@ High-k Gate Oxides for Thin Film Transistors

Thursday, November 16, 2006, 5:30 pm, Room 3rd Floor Lobby

Session: Electronic Materials and Processing Poster Session
Presenter: S.W. Jeong, Sungkyunkwan University, Korea
Authors: S.W. Jeong, Sungkyunkwan University, Korea
K.-S. Kim, Sungkyunkwan University, Korea
J.-Y. Son, Sungkyunkwan University, Korea
Y. Roh, Sungkyunkwan University, Korea
Correspondent: Click to Email
Recently, high-k materials are under consideration as replacements for SiO@SUB2@. Among some metal oxides, HfO@sub2@ is an attractive candidate due to their high dielectric constant and thermal stability in contact with silicon. And Al@SUB2@O@SUB3@ is an another attractive candidate because Al@SUB2@O@SUB3@ can remain amorphous at temperature higher than 900@degree@C. The aim of this study is to investigate the thermal stability of the HfO@sub2@ based films with Al@sub2@O@sub3@. Hf metal films were deposited on the (100) p-type Si/Al@sub2@O@sub3@ substrates (100) p-type Si wafers in sequence by non-reactive magnetron sputtering at room temperature. The Hf metal films deposited on the Si/Al@sub2@O@sub3@ substrate were then subjected to oxidation in O@sub2@ ambient at 500 @degree@C for 60 minutes in furnace. We proposed a new technique to grow Al@sub2@O@sub3@/HfO@sub2@ films on the Si substrate at 500 @degree@C. Oxidation followed by annealing of sputtered Hf metal films on the Si substrate both at 500 @degree@C results in multi-layered Al@sub2@O@sub3@-HfO@sub2@ gate insulator. HfO@sub2@/Al@sub2@O@sub3@ laminate structure ware maintained, and Al@sub2@O@sub3@ layer was not useful for blocking oxygen diffusion due to interfacial layer growth. Crystallization temperature of the HfO@sub2@/Al@sub2@O@sub3@ thin films which has Al@sub2@O@sub3@ was delayed up to 900 @degree@C, and as concentration of the Al@sub2@O@sub3@ in HfO@sub2@/Al@sub2@O@sub3@ thin films increases, thermal stability improved. As an annealing temperature increases, HR-TEM analyses of the all the HfO@sub2@/Al@sub2@O@sub3@ flims show the increased interfacial layer thickness. Therefore, our results show the addition of Al@sub2@O@sub3@ is not useful for blocking oxygen diffusion through the HfO@sub2@/Al@sub2@O@sub3@ thin film. From the C-V and I-V measurements, calculated leakage current of the HfO@sub2@/Al@sub2@O@sub3@ thin films was ~16, and as an annealing temperature increases, the leakage current of the films was improved.