CONFORMAL CHEMICAL BEAM DEPOSITION OF THIN METAL-FILM FOR FABRICATING HIGH-DENSITY TRENCH CAPACITOR CELLS

The difficult aspect of conformal metal film deposition in narrow, high aspect ratio trenches such as those used in the fabrication of high density metal-oxide-semiconductor trench capacitor cells for computer memory technology is addressed. This work demonstrates the proof of principle of highly conformal deposition of a 40 nm Pt film on the surfaces of a 0.5-mum-wide, 1.5-mum-deep, and 2-mm-long array of oxidized silicon trenches, using the thermal decomposition of a molecular precursor under chemical beam conditions. In addition, scanning electron, x-ray photoelectron, and scanning Auger electron microscopy analyses reveal highly uniform and complete coverage on all surfaces, small metal grain size, and the absence of detectable impurities.