Cubic-Structured HfO2 With Optimized Doping of Lanthanum for Higher Dielectric Constant

Silicon Nano Device Lab., Nat. Univ. of Singapore, Singapore
IEEE Electron Device Letters (Impact Factor: 3.02). 07/2009; 30(6):623 - 625. DOI: 10.1109/LED.2009.2020613
Source: IEEE Xplore

ABSTRACT It is demonstrated that HfO2 films can have much higher dielectric-constant values than the usual reported value of 20-24 by optimized incorporation of lanthanum element and crystallization to cubic structure. When HfO2 with 8% La is crystallized into cubic structure, the film exhibits the kappa value of ~38 which is the highest among ever reported HfO2 -based high-kappa dielectrics. The increased kappa value of HfO2 with 8% La enables the leakage current to be reduced more than one order of magnitude lower, compared to amorphous-phase HfO2 under the same electric field. The dependence of film thickness and annealing temperature on the cubic crystallization is also reported.

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    • "(b) Benchmarked data on leakage current densities (at +3V) versus EOT. to form the bottom-gate electrode. A 20-nm-thick HfLaO with 8% La concentration was then deposited by an atomic layer deposition process [13]. The chamber pressure and temperature for HfLaO deposition were 0.2 torr and 300 • C, respectively. "
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