Amorphous Ni-Nb alloys are of potential interest as diffusion barriers for high temperature metallization for VLSI. In the present work amorphous Ni-Nb films were sputter deposited on Si(100) and their interaction with a substrate was studied in the temperature range (200-700)°C. The crystallization of films was observed on the plan-view specimens heated in-situ in Philips-400ST microscope. Cross-sectional objects were prepared to study the structure of interfaces.The crystallization temperature of Ni5 0 Ni5 0 and Ni8 0 Nb2 0 films was found to be equal to 675°C and 525°C correspondingly. The crystallization of Ni5 0 Ni5 0 films is followed by the formation of Ni6Nb7 and Ni3Nb nucleus. Ni8 0Nb2 0 films crystallise with the formation of Ni and Ni3Nb crystals. No interaction of both films with Si substrate was observed on plan-view specimens up to 700°C, that is due to the barrier action of the native SiO2 layer.

Reactions of thin policrystalline Ni and amorphous Ni—Nb films with a Si (100) substrate in the temperature range of 200 to 770°C are studied by TEM, SEM, AES, and EDX methods. The crystallization of the Ni—Nb films is observed in‐situ in the TEM. The interaction of the Ni—Nb films with the substrate occurs above the crystallization temperature of the films and is found to be dependent on the heating rate. The reactions are accompanied by a phase separation process and the formation of large Ni silicide islands inside the substrate. No reaction of Ni films with Si is observed up to 650°C in the presence of a native SiO2 layer at the interface. An action of the stress gradients in Ni—Nb films and the corresponding formation of pinholes in the underlying native SiO2 layer is proposed to explain the results obtained.

The crystal struct.ure of thermally oxidized Ge was invcst.igated by high-resolution electron microscopy (HREM), mainly the interfacc Ge/oxide. Under special conditions tho readion Ge + 0, + GeO, which takes place at (111) surface planes leads t o suitable t)hin crystal regions. The GeO, occurs normally as amorphous films on the crystal surface.Furthernlore, hexagonal GeO, can grow at the interface Ge/oxide by a topotaxial reaction ; t,he orientation relation between these two lattices was ascertained. Intensive electron irradiation was used t o initiate and to observe structure changes in boundary regions.Die Kristallstrukt.ur von therrnisch oxidierteii Ge Kristallen wurde iiiit Hilfe der HochauflSsungsmikroskopie (HREM) untersucht, hauptsiichlich die Grenzfliiche Ge/Oxid.

Pd-W alloy films are of interest because of their use for contact fabrication in microelectronic devices.In the present work Pd2 5W7 5, Pd4 0W6 0, Pd9 0W1 0 films were sputter deposited on Si(100) and only Pd9 0W1 0 films were polycrystalline.The amorphization of Pd- W films, possibly due to impurities, was not observed previously. The reaction of Pd9 0W1 0 films with a Si substrate begins at 200°C and leads to the formation of Pd2Si in two equivalent epitaxial orientations: A and B.In contrast to Ni-Nb films the presence of the native SiO2 layer under Pd-W alloy does not prevent the diffusion processes and the formation of silicides both on bulk and on plan-view specimens.Amorphous Pd-W films do not react with Si up to∼500°C and their crystallisation begins at T∼575°C.The reaction is also followed by the formation of two types of epitaxially oriented Pd2 Si islands as shown in Figure 1.The crystallisation of the films is accompanied by the formation of W grains.Pd crystals were not observed, that is possibly due to Pd precipitation at W grain boundaries.

Thin films of amorphous Ni-Nb alloys are of interest since they can be used as diffusion barriers for integrated circuits on Si. A native SiO2 layer is an effective barrier for Ni diffusion but it deformation during the crystallization of the alloy film lead to the appearence of diffusion fluxes through it and the following formation of silicides. This study concerns the direct evidence of the action of stresses in the process of the crystallization of Ni-Nb films on Si and the structure of forming NiSi2 islands.