Influence of Deposition Temperature of Atomic-Layer-Deposited HfO2 Films on Interfacial Chemical Structure and Interface Trap Density

• Published in: ECS transactions Vol. 1; no. 5; pp. 419 - 424
• Main Authors: Kim, Jeong Hwan, Park, Taejoo, Hwang, C.S., Hong, Sug H., Seo, Minha
• Format: Journal Article
• Language: English
• Published: 07.07.2006
• ISSN: 1938-5862; 1938-6737
• DOI: 10.1149/1.2209291

The influence of the deposition temperature (250oC and 300oC) and oxidant (O3) concentration during atomic layer deposition of HfO2-gate dielectrics on the dielectric performance of the films grown on Si using Hf([N(CH3)(C2H5)]3[OC(CH3)3]) or Hf[N (CH3)2]4 as the Hf-precursor was studied. In case of HfO2 thin films, the deposition temperature affects the interfacial trap density (Dit): The lower the deposition temperature is, the better is Dit. Investigation of the interface states using X- ray photoelectron spectroscopy revealed that HfO2 thin films that show a lower Dit include more SiN and silicate relative to SiO2. The depth profiles of the chemical composition of the film stacks taken by secondary ion mass spectroscopy confirmed that silicate reaction was predominant over the re-oxidation reaction of Si substrate. Judging from this, a better interface property can be obtained at a lower deposition temperature due to the densely formed SiN layer and the predominant silicate reaction which suppress a harsh re- oxidation (Si4+) in the interface.