Full Paper: Microtrench step coverage mechanisms are studied in silicon-based systems. The microtrench coverage of silicon, SIPOS, in situ boron-doped and in situ phosphorus-doped silicon (see Figure) is investigated using LP-CVD by comparing experimental and simulation results deduced from two trench-scale diffusion-reaction models. New opportunities are opened up in terms of design of the shape and dimensions of trenches with respect to each deposit kinetic characteristic.