A guanidinate silane compound of any of formulae (I)-(IV) is described, having utility as a precursor in vapor deposition processes for forming a silicon-containing film on a substrate. The guanidinate silane compound can be used in vapor deposition processes such as chemical vapor deposition and atomic layer deposition, at temperatures below 400° C., to form silicon-containing films, e.g., silicon nitride films, useful as diffusion barrier layers, etch stop layers, and sidewall coating films, in integrated circuitry, flat-panel displays, solar panels, and other microelectronic and optoelectronic applications.