Silicon germanium processing

A method of etching germanium, the method comprising:

• flowing a fluorine-containing precursor into a remote plasma region fluidly coupled to a substrate processing region via through-holes in a showerhead;
• flowing a diluent gas into either the remote plasma region or the substrate processing region;
• forming a remote plasma in the remote plasma region to produce plasma effluents;
• and
• etching the germanium from a patterned substrate disposed within the substrate processing region by flowing the plasma effluents into the substrate processing region through the through-holes in the showerhead, wherein the patterned substrate further comprises exposed regions of silicon germanium and the germanium is etched faster than the silicon germanium, wherein each point on an exposed surface of the germanium of is within 0.5 μm of a point on a region of exposed silicon germanium.

A method of etching a semiconducting layer, the method comprising:

• transferring a patterned substrate into a substrate processing region, wherein the patterned substrate comprises regions of Si(1-X)GeX and Si(1-Y)GeY, and wherein X>Y;
• flowing a fluorine-containing precursor into a remote plasma region fluidly coupled to a substrate processing region via through-holes in a showerhead;
• forming a remote plasma in the remote plasma region to produce plasma effluents from the fluorine-containing precursor;
• and
• etching Si(1-X)GeX at a first etch rate and etching the Si(1-Y)GeY at a second etch rate by flowing the plasma effluents into the substrate processing region through the through-holes in the showerhead, wherein each point on an exposed surface of the Si(1-X)GeX region of is within 0.5 μm of a point on a region of exposed Si(1-Y)GeY.