This title appears in the Scientific Report :
2003
Please use the identifier:
http://hdl.handle.net/2128/179 in citations.
Lasersinterung keramischer Dünnschichten
Lasersinterung keramischer Dünnschichten
Electroceramic materials have a large application potential in microelectronics due to their electrical properties. Technologies are therefore being investigated for the deposition of the ceramics as thin films into semiconductor components. The establishment of a very Iowtemperature process is adva...
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Personal Name(s): | Baldus, Karl Josef Oliver (Corresponding author) |
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Contributing Institute: |
Elektronische Materialien; IFF-IEM |
Imprint: |
Jülich
Forschungszentrum Jülich GmbH Zentralbibliothek, Verlag
2003
|
Physical Description: |
114 p. |
Dissertation Note: |
Aachen, Techn. Hochsch., Diss., 2003 |
Document Type: |
Book Dissertation / PhD Thesis |
Research Program: |
Materialien, Prozesse und Bauelemente für die Mikro- und Nanoelektronik |
Series Title: |
Berichte des Forschungszentrums Jülich
4047 |
Subject (ZB): | |
Link: |
OpenAccess |
Publikationsportal JuSER |
Electroceramic materials have a large application potential in microelectronics due to their electrical properties. Technologies are therefore being investigated for the deposition of the ceramics as thin films into semiconductor components. The establishment of a very Iowtemperature process is advantageous for the integration of electroceramics into silicon technology. Deposition temperatures of at maximum 450°C are necessary in order to avoid hterface reactions of the substrate with the dielectric layer and the formation of intermetallic phases in the electronic component. The minimum crystallization temperature of the titanates and related materials of at least 600°C comes into conflict with this requirement. The reason for the interest in the laser sintering of oxidic thin films, which are amorphously cbposited at low temperatures, is the additional degrees of freedom in comparison to the thermal treatment in a conventional furnace. These additional degrees of freedom comprise variations in the irradiation time (fs to s), irradiated area (10nm$^{2}$ to 4cm$^{2}$) and the temperatures achieved (1k..evaporation). The laser process thus enables the thermal load an the substrate to be reduced by minimizing the integaction time between the heating source and the ceramic layer. In the present work, thin films of barium-strontium-titanate (BST) and lanthanum-calciummanganite (LCM) are deposited amorphously and sintered with nanosecond UV laser pulses. The aim is to investigate fundamental aspects of the solid-state physics and process technology during the laser sintering of amorphous, electroceramic thin films. The conditions under which a sintering of the thin films can be achieved with UV lamps are also investigated. The experimental approach consists in the wet-chemical deposition of amorphous films sintered by a KrF or ArF excimer laser or a Nd:YAG laser. Adjusting the film thicknesses avoids damage to the Ceramic thin films by the laser treatment. Planar test structures are manufactured and characterized structurally and electrically. The characterization of the BST films results in clearly improved dielectric properties in contrast to the amorphous films. The real pari of the dielectric constant can be raised three- to fivefold at 10kHz, while the imaginary pari decreases by nearly an order of magnitude. The LCM films, which are electrically insulating in the amorphous phase, become semiconducting by laser crystallization ($\sim$1$\Omega$cm). Furthermore, the laser parameters can be correlated with data from the electrical characterization. The chemical analysis does not indicate any significant changes in the stoichiometry of the thin films due to the laser process. The laser-induced changes proceed in a similar manner to the crystallization of the amorphous films in the furnace. Parallel to the experimental work, a numerical simulation model is developed, which, an the basis of the thermal conduction, the Johnson-Mehl-Avrami crystallization kinetics and the thermoelasticity, models the temperature, the crystallization and the mechanical load an the thin films. The simulation calculations are correlated with the results of the analysis of the laser-treated samples. |