Thin films instabilities

The rupture process of a soap film is of some interest. In the case of a film spanning a frame, as in Fig. XIV-15, it is known that rupture tends to originate at the margin, as shown in the classic studies of Mysels [207, 211]. Rupture away from a border may occur spontaneously but is usually studied by using a spark [212] as a trigger (a-radia-tion will also initiate rupture [213]). An aureole or ridge of accumulated material may be seen on the rim of the growing hole [212, 214] (see also Refs. 215, 216). Theoretical analysis has been in the form of nucleation [217, 218] or thin-film instability [219]. 

G. Reiter, A. Sharma, A. Casoli, M.-O. David, R. Khanna, and P. Auroy, Thin film instability... 

In spite of the above-mentioned advantages of UTR processes, practical considerations often impose a choice of resist and substrate that are not fully compatible, resulting in films that are unstable or metastable with finite relaxation time. While thick films (> 300 nm) may be stable or metastable due to gravityfor thin films (<100 nm) intermolecular and surface forces dominate. UTR films are susceptible to both spontaneous thin-film instabilities due to London-van der... 

Okoroanyanwu, Thin film instabilities and implications for ultra thin resist process J. Vac. Sci. Technol. B 18(6), 3381 3387 (2000) U. Okoroanyanwu, Limits of ultra thin resist process Future Fab. Int 10, 157 163 (2001). 

Thin film instability enhanced by external electric field... 

Another described method of polymer surface modificahon consists in application of thin film instability enhanced by external electric field. Linear structures were created by the effect of locally limited electric field in thin polymer films heated to fluid temperature. 

Instabilities of thin liquid films have been investigated for many decades. The general contours of the mechanics and thermodynamics of thin-film instability have emerged during the last 50 years. " " On the theoretical side, Sheludko and Vrij " ... 

The condition of instability vis-a-vis stability of a thin film in terms <6 or II (or AG) as a function of h emerges from linear stability analysis (LSA) [33-38,65]. In order to facilitate the discussion of LSA, a brief summary of the kqr theoretical results on thin film instability is presented here. 

D. J. Srolowitz, S. A. Safran. Capillary instabilities in thin films. J Appl Phys 60 247-260, 1986. 

Photovoltaic response parameters for electrodeposited (polycrystalline) CdTe thin film electrodes in sulfide-polysulfide or alkaline sodium telluride PEC have been reported, primarily with no reference to the stability of the cells [100], In view of the instability of CdTe in aqueous solutions, Bhattacharya and Rajeshwar [101] employed two methods for the characterization of their electrodeposited CdTe-based PEC. In the first one, a coating of Pb02 (-100 nm thick) was deposited on the CdTe film surface by electroless deposition, and the coated films... 

MJ Powell, C van Berkel, and JR Hughes, Time and temperature dependence of instability mechanisms in amorphous silicon thin-film transistors, Appl. Phys. Lett., 54 1323-1325, 1989. 

CNT conductive surface modification Both SWNTs and MWNTs can be deposited directly from a CNT dispersion as a random network or thin film on conventional electrodes. From the point of view of their construction such electrodes are very easy to prepare but they may suffer from mechanical instability, thus limiting their application. 

In general, surface morphological instabilities driven by stresses are an important subject to investigate in connection with microelectronic applications. In particular, the degree of surface waviness in thin films as a consequence of surface and volume diffusion is a matter of pivotal importance. This topic has attracted considerable attention in the last two or so decades (11). Although surface diffusion is an important kinetic process, other kinetic processes may affect the evolution of stressed surfaces. Indeed, a possibility at high temperatures is the diffusion of atoms through the bulk. 

Let us examine the instability oi strained thin films. In Fig. 3, thin films of30 ML are coherently bonded to the hard substrates. The film phase has a misfit strain, e = 0.01, relative to the substrate phase, and the periodic length is equal to 200 a. The three interface energies are identical to each other = yiv = y = Y Both phases are elastically isotropic, but the shear modulus of the substrate is twice that of the film (p = 2p). On the left-hand side, an infinite-torque condition is imposed to the substrate-vapor and film-substrate interfaces, whereas torque terms are equal to zero on the right. In the absence of the coherency strain, these films are stable as their thickness is well over 16 ML. With a coherency strain, surface undulations induced by thermal fluctuations become growing waves. By the time of 2M, six waves are definitely seen to have established, and these numbers are in agreement with the continuum linear elasticity prediction [16]. 

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