Frequency dispersion effect and parameters extraction method for novel HfO2 as gate dielectric
The electric characteristic of MOS capacitor with HfO2/SiO2/p-Si grown by ALCVD (atom layer chemical vapor deposition) is investigated. The C-V curves show that the accumulation capacitances take on the frequency dispersion at high frequency. For MOS capacitor with ultra thin HfO2/SiO2 gate stack, different fabrication processes and measurement equipment will cause parasitic effect. Here an equivalent circuit model that can eliminate the frequency dispersion effect is proposed. The C-V characteristics curve at high frequency shows some distortion because of the bulk defects and the interface states. This paper discusses the distortion of the high frequency MOS C-V characteristic curve. A data processing method is advanced and interface trap density distribution in the band gap is presented. By comparing the ideal C-V curve with the experimental C-V curve, the typical electrical parameters of MOS capacitor are extracted, including the shift of flat-band voltage, the oxide charges and the density of interface traps at the SiO2/Si interface.
Keywordshigh k gate dielectric HfO2 frequency dispersion equivalent circuit model two-frequency C-V measurement parameters extraction
- 3.Deshpande A S. Fundamental studies on alternative high-k gate dielectric materials. Dissertation for the Doctoral Degree. Chicago: University of Illinois at Chicago, 2005. 133–138Google Scholar
- 6.Barlage D, Arghavani R, Dewaey G, et al. High-frequency response of 100 nm integrated CMOS transistors with high-k gate dielectrics. IEDM Tech Dig, 2001, 47: 1–4Google Scholar
- 10.Liu H X, Cai N Q. An improved two-frequency method with four-element circuit model for the novel HfO2 as the gate dielectric (in Chinese). J Xidian Univ, 2008, 35: 1051–1055Google Scholar