Formation of “negative” silicon whiskers

An approach has been proposed for producing “negative” whiskers in Si wafers which is based on the thermal migration of silicon–metal (Si + M) melt droplets in the field of a transverse temperature gradient. We have obtained regular systems of negative whiskers in the form of through holes in Si {111} wafers. It has been shown that the thermal migration of Si + M melt droplets is driven by the difference between the chemical potentials of Si in the liquid and crystalline phases, which arises from the difference in curvature between the liquid/vapor and solid/liquid interfaces and leads to Si dissolution and desorption.