Method of filling trenches using vapor-liquid-solid mechanism

Abstract

A method of filling trenches such as a DT cell with silicon is described that involves a vapor-liquid-solid (VLS) mechanism. First, a thin film of Si is grown on the trench sidewalls. Seed metal such as Au, Ni or Ni alloy is deposited on the sidewalls by an electroless plating process. A thermal treatment is then used to reflow the metal to a liquid state art the trench bottom. A Si precursor gas is applied to grow a single whisker that fills the trench. Silicon overgrowth is removed by an etch or CMP step. The method can also be applied to filling a via hole with silicide. In this case the seed metal is Ti, Co, or Ni which is reflowed by a thermal treatment. A silicon source gas like SiCl4 is combined with H2 to grow the silicide layer. This method is especially useful in forming seamless fill layers.

Dependencies are inferred from the claim text.