Low-frequency noise characteristics for various ZrO2-added HfO2-based 28-nm High-k/metal-gate nMOSFETs

Shih Chang Tsai, San Lein Wu, Bo Chin Wang, Shoou Jinn Chang, Che Hua Hsu, Chih Wei Yang, Chien Ming Lai, Chia Wei Hsu, Osbert Cheng, Po Chin Huang, Jone F. Chen

Research output: Contribution to journalArticlepeer-review

15 Citations (Scopus)


In this letter, the effect of adding ZrO2 to different positions in an HfO2-based high-k (HK) gate-stack is investigated by a low-frequency (1/ f ) noise measurement. The tested nMOSFETs are fabricated using 28-nm gate-last HK/metalgate technology with a ∼1-nm SiO2 interfacial layer. The 1/ f noise mechanism of these devices is described by the carrier number fluctuation, and the extracted trap densities (Nt) are 8.9 × 1018- 5.1 × 1019 eV-1 cm -3. However, reference devices with a pure ZrO2 gate dielectric exhibit 1/ f noise characteristics that are consistent with the unified model, which incorporates both the carrier number and the correlated mobility fluctuations. The reference devices are with lower Nt values in the range of 5.8 × 1017 - 2.4 × 1018 eV-1 cm-3. In addition, there is an increase in Nt as the initial HfO2 layer becomes thicker. These results show that the trapping behavior is mainly dominated by the HfO2 film and is dependent on the thickness of the initial HfO2 layer in the ZrO 2/HfO2/SiO2 gate-stack.

Original languageEnglish
Article number6525388
Pages (from-to)834-836
Number of pages3
JournalIEEE Electron Device Letters
Issue number7
Publication statusPublished - 2013

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Electrical and Electronic Engineering


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