In this study, different surface treatments of HF-based etching solutions are investigated for the predeposition of liquid-phase deposited fluorinated silicon oxides (LPD-SiOF). The effects of each etching solution on the interface trap density and breakdown field are examined with Al/LPD-SiOF/Si structure. From the experimental results, there appears significant growth delay time for different surface treatments during the initial oxide deposition, which is defined as the surface modification time to reach an OH-rich surface promoting the growth of LPD-SiOF film. However, the subsequent deposition rate remains unchanged for all etching processes, indicating a surface-independent deposition process. It is found that a two-step treatment in dilute HF/H2O with 1:200 v/v ratio reveals an average breakdown field of 9.7 MV/cm and an extremely low average interface trap density (approximately 1010 eV-1 cm-2), which are comparable to that of thermal oxides. Moreover, the rapid thermal annealing process is suggested to clearly improve the oxide quality for this two-step etching process, where early breakdown is eliminated (18% raising for EBD) and interface properties are substantially improved (33% reduction for DH). The improvements for device performances are believed to be due to the oxide-free Si surface passivated with hydrogen and reduced surface microroughness (Ra = 0.1 nm). It is evident from our experiments that this new two-step surface treatment is an effective method for interface improvement with oxide deposited by LPD or chemical vapor deposition.
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Renewable Energy, Sustainability and the Environment
- Surfaces, Coatings and Films
- Materials Chemistry