The aim of this paper is to emphasise the correlation between film preparation conditions, film properties and their applications, Low pressure chemical vapour deposition amorphous silicon carbide (a-SiC) and silicon carbonitride (SiCN) films obtained from liquid precursors have different structure and composition depending on deposition conditions. Thus, the films deposited under kinetic working conditions reveal a stable structure and composition. Deposition at moderate temperature leads to stoichiometric SiC, while the films deposited at high temperatures have a composition closer to Si1-xCx, with x = 0.75, These films form a very reactive interface with metallic layers. The films realised under kinetic working regime can be used in Si membrane fabrication process or as coating films for field emission applications. SiC layers field emission properties were investigated; the field emission current density of the a-SiC/Si structures was 2.4 mA/cm(2) at 25 V/mum. An Si membrane technology based on moderate temperatures (770-850 degreesC) a-SiC etching mask is presented.