Interaction of thin films of Ni and Ni—Nb alloys with Si the action of the native SiO2 layer

Abstract

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.