Physical properties of room temperature deposited B-C-N-O films prepared by dual-ion-beam deposition

B-C-N-O films with various compositions were prepared at room temperature u sing dual-ion-beam deposition. The films are divided into three groups, wit h C contents below 10 at.%, between 10 and 35 at.%, and above 35 at.%, resp ectively. The films of the first group are dominated by the existence of a B-O phase. They have wider optical band gaps E-g, and are therefore more tr ansparent and insulating. The volume fraction of the B-O phase decreases wi th increasing C content, thereby leading to a drop in the hardness H. The s econd group of films contains a h-BN phase, and so have smaller E-g and hig her room temperature electrical conductivity sigma(room). H rises and appro aches that of h-BN when the C content reaches 35 at.%. The third group of f ilms contains a large fraction of a graphite phase, which greatly affects t he films properties, leading to a further reduction of E-g and a rise in si gma(room). H becomes lower with increasing C content. This work demonstrate s that the optical, electrical and mechanical properties of B-C-N-O films c an be tailored by adjusting the composition. (C) 1999 Elsevier Science S.A. All rights reserved.