Effects of annealing temperature on the characteristics of ALD-deposited HfO2 in MIM capacitors

We have investigated the annealing effects of HfO2 films deposited by an atomic layer deposition (ALD) method on the electrical and physical properties in the Si/SiO2/Pt/ALD-HfO2/Pd metal-insulator-metal (MIM) capacitors. If the annealing temperature for HfO2 films was restricted below 500 degrees C, an annealing step using a rapid thermal processor (RTP) improves the electrical properties such as the dissipation factor and the dielectric constant. On the other hand, annealing at 700 degrees C degrades the electrical characteristics in general; the dissipation factor increases over the frequency range of 1 similar to 4 MHz, and the leakage current increases up to 2 orders at the low electric field regions. We found that the degradation of electrical properties is due to the grain growth in the HfO2 film (i.e., poly-crystallization of the film) by the high temperature annealing processing. We suggested that the annealing temperature must be restricted below 500 degrees C to obtain the high quality high-k film for the MIM capacitors. (c) 2005 Elsevier B.V. All rights reserved.