The deposition of high-quality SiO2 films has been achieved through the use of both plasma-enhanced chemical vapor deposition (PE-CVD) and plasma-enhanced atomic layer deposition (PE-ALD) methods using H2Si[N(C2H5)2]2 as a Si precursor. We systematically investigated growth characteristics, chemical compositions, and electrical properties of PE-CVD SiO2 prepared under various deposition conditions. The SiO2 films prepared using PE-CVD showed high purity and good stoichiometry with a dielectric constant of ~4. In addition, the PE-ALD process of the SiO2 films exhibited well-saturated and almost linear growth characteristics of ~1.3 Å cycle−1 without notable incubation cycles, producing pure SiO2 films. Electrical characterization of metal-oxide silicon capacitor structures prepared with each SiO2 film showed that PE-ALD SiO2 films had relatively lower leakage currents than PE-CVD SiO2 films. This might be a result of the saturated surface reaction mechanism of PE-ALD, which allows a smooth surface in comparison with PE-CVD method. In addition, the dielectric properties of both SiO2 films were further evaluated in the structures of In–Ga–Zn–O thin-film transistors, and they both showed good device performances in terms of high Ion − Ioff ratios (>108) and low off-currents (<10−11 A). However, based on the negative bias stress reliability test, it was found that PE-ALD SiO2 showed better reliability against a negative Vth shift than PE-CVD SiO2, which might also be understood from its smoother channel/insulator interface generation at the interface.
Bibliographical noteFunding Information:
This work was supported by Korea Evaluation Institute of Industrial Technology (KEIT) funded by the Ministry of Trade, Industry and Energy (MOTIE) (Project No. 10050296, Large scale (Over 8?) synthesis and evaluation technology of 2-dimensional chalcogenides for next generation electronic devices) and supported by the Industrial Strategic technology development program (10041926, Development of high density plasma technologies for thin-film deposition of nanoscale semiconductor and flexible display processing) funded by the Ministry of Knowledge Economy (MKE, Korea) and supported by the National Research Foundation of Korea (NRF) Grant funded by the Korea government (MSIP) (No. NRF-2014R1A2A1A11052588). Also this work was supported by Samsung Display Co., Ltd.
All Science Journal Classification (ASJC) codes
- Materials Science(all)
- Mechanics of Materials
- Mechanical Engineering