In Situ TEM Study of the Amorphous-to-Crystalline Transition during Dielectric Breakdown in TiO 2 Film
Dielectric breakdown of oxides is a main limiting factor for improvement of the performance of electronic devices. Present understanding suggests that defects produced by intense voltage accumulate in the oxide to form a percolation path connecting the two electrodes and trigger the dielectric breakdown. However, reports on directly visualizing the process at nanoscale are very limited. Here, we apply in situ transmission electron microscopy to characterize the structural and compositional changes of amorphous TiO2 under extreme electric field (~100 kV/mm) in a Si/TiO2/W system. Upon applying voltage pulses, the amorphous TiO2 gradually transformed to crystalline sub-stoichiometric rutile TiO2-x and the Magnéli phase Ti3O5. The transitions started fromat the anode/oxide interface under both field polarities. Preferred growth orientation Epitaxial growth of rutile TiO2-x with respect toon the Si substrate was observed when Si was the anode, while oxidation and melting of the W probe occurred when W was the anode. We associate the TiO2 crystallization process with the electrochemical reduction of TiO2, polarity-dependent oxygen migration, and Joule heating. The experimental results are supported by our phase-field modeling. These findings provide direct details of the defect formation process during dielectric breakdown in amorphous oxides and will help the design of electronic devices with higher efficiency and reliability.
- Research Organization:
- Iowa State Univ., Ames, IA (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22). Materials Sciences & Engineering Division
- Grant/Contract Number:
- SC0017839
- OSTI ID:
- 1594025
- Journal Information:
- ACS Applied Materials and Interfaces, Vol. 11, Issue 43; ISSN 1944-8244
- Publisher:
- American Chemical Society (ACS)Copyright Statement
- Country of Publication:
- United States
- Language:
- English
Web of Science
Similar Records
Direct Observations of Field-Intensity-Dependent Dielectric Breakdown Mechanisms in TiO2 Single Nanocrystals
Physical and optical properties of room temperature microwave plasma anodically grown TiO{sub 2}