High resolution transmission electron microscopy of metallic film/laser-irradiated alumina couples
- Tennessee Univ., Knoxville, TN (United States)
- Oak Ridge National Lab., TN (United States)
A near-surface thin layer is melted when single crystal alumina (sapphire) is pulsed laser-irradiated in an Ar-4%H{sub 2} atmosphere. {gamma}-alumina grows epitaxially from the (0001) face of {alpha}-alumina (sapphire ) during the rapid solidification of this layer that occurs once the laser pulse is over. Cross sectional high resolution transmission electron microscopy (HRTEM) reveals that the interface between unmelted sapphire and {gamma}-alumina is atomistically flat with steps of one to a few close-packed oxygen layers; however, pronounced lattice distortions exist in the resolidified {gamma}-alumina. HRTEM also is used to study the metal-ceramic interface of a copper film deposited on a laser-irradiated alumina substrate. The observed changes of the interfacial stricture relative to that of unexposed substrates are correlated with the strong enhancement of film-substrate bonding promoted by laser irradiation. HRTEM shows that a thin amorphous film is produced after irradiation of 99.6% polycrystalline alumina. Formation of a diffuse interface and atomic rearrangements that can take place in metastable phases contribute to enhance the bonding strength of copper to laser-irradiated alumina.
- Research Organization:
- Oak Ridge National Lab., TN (United States)
- Sponsoring Organization:
- National Science Foundation, Washington, DC (United States); USDOE, Washington, DC (United States)
- DOE Contract Number:
- AC05-84OR21400
- OSTI ID:
- 207585
- Report Number(s):
- CONF-951155--48; ON: DE96005399; CNN: Grant DMR-9116528
- Country of Publication:
- United States
- Language:
- English
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