Thin-film deposition thermal stability

T. Minemura, J.J. Van den Broek, J.L.C. Daama, Formation and thermal stability of amorphous Cu-Zr thin films deposited by co-evaporation, J. Appl. Phys. 63 (1988) 4426. 

The Langmuir-Blodgett (LB) technique was successfully applied for the deposition of thin protein layers (Langmuir and Schaefer 1938, Tiede 1985, Lvov et al. 1991). LB organization of protein molecules in film not only preserved the structure and functionality of the molecules, but also resulted in the appearance of new, useful properties, such as enhanced thermal stability (Nicolini et al. 1993 Erokhin et al. 1995). 

Phthalocyanines (Pc) are attractive materials for their potential functions including the semiconductive behaviours in addition to the thermal and chemical stabilities. In particular, control of orientation of the Pc macrocycles in thin films is expected to provide novel molecular electronic devices. Previously, we have found that copper tetrakis(butoxycarbonyl) Pc is oriented nearly perpendicular to the surface and also the dipping direction in the LB films [46], while octa-alkyl Pc derivatives [H2Pc(R)8, CuPc(R)a R = CnH2n+i. n=7,9,11] take the orientation with Pc macrocycles nearly parallel to the plane of films deposited by the horizontal lifting method to form a non-alternating X-type film [47], as illustrated schematically in... 

Thin films, to attain enough sensitivity and response time, of oxide materials normally deposited on a substrate are typically used as gas sensors, owing to their surface conductivity variation following surface chemisorption [183,184], Surface adsorption on a Sn02 film deposited on alumina produces a sensitive and selective H2S gas sensor [185]. In addition, a number of perovskite-type compounds are being used as gas sensor materials because of their thermal and chemical stabilities. BaTi03, for example, is used as sensor for C02 [183],... 

As the VDP of polyimides involves two precursors, diamine and dianhydride, the relative amounts of fluxes of the precursor vapors need to be controlled carefully to obtain high quality polyimide thin films. The effects of both excess dianhydride as well as the diamine components have been studied and reported in literature, It was observed that, excess dianhydride (PMDA) undergoes desorption when cured after deposition leading to poor thermal stability. 

The post deposition processing parameters (curing temperature, time) have a profound impact on the thermal properties of polyimide thin films. It has been observed that, films cured at around 300°C for 1 hour exhibit markedly superior thermal stability as compared to those that were not cured." ° Cured PMDA-ODA... 

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