US Patent 7973302 Forming phase change memory cells

Small phase change memory cells may be formed by forming a segmented heater over a substrate. A stop layer may be formed over the heater layer and segmented with the heater layer. Then, sidewall spacers may be formed over the segmented heater to define an aperture between the sidewall spacers that may act as a mask for etching the stop layer over the segmented heater. As a result of the etching using the sidewall spacers as a mask, sublithographic pore may be formed over the heater. Phase change material may be formed within the pore.