Effect of H2S pre-annealing treatment on interfacial and electrical properties of HfO2/Si1−xGex (x = 0–0.3)

• Published in: Journal of materials chemistry. C, Materials for optical and electronic devices Materials for optical and electronic devices, 2021-02, Vol.9 (5), p.1829-1835
• Main Authors: Lee, Woohui, Lee, Changmin, Kim, Jinyong, Lee, Jehoon, Eom, Deokjoon, Jae Chan Park, Park, Tae Joo, Kim, Hyoungsub
• Format: Article
• Language: English
• Subjects: Annealing; Electrical properties; Germanium; Hafnium oxide; Hydrogen sulfide; Oxidation; Pretreatment; Silicon germanides; Substrates
• ISSN: 2050-7526; 2050-7534
• DOI: 10.1039/d0tc04760k

To understand the effect of H2S pre-annealing treatment on a Si1−xGex alloy film, the interfacial and electrical characteristics of atomic-layer-deposited HfO2/Si1−xGex were studied while varying the Ge concentration (x value) from 0 to 0.3. H2S pre-annealing was performed on the Si1−xGex substrates at 400 °C for 30 s using a rapid thermal annealing system prior to the HfO2 deposition. As the Ge concentration in Si1−xGex increased, the H2S pretreatment caused a greater increase in the capacitance-equivalent oxide thickness because of accelerated interfacial oxidation by a thermal annealing side effect. However, it was advantageous in reducing the interface state density on a Ge-rich surface, which suggested effective sulfur passivation on the Ge dangling bonds at the HfO2/Si1−xGex interface. Furthermore, the H2S pretreatment was effective in suppressing the out-diffusion of Ge towards the HfO2 film, which was beneficial in improving the near-interface charge trapping characteristics.