Optical Waveguide Structure and Method of Manufacture Thereof
A method of manufacture of an optical waveguide structure including the steps of: providing a multilayer semiconductor wafer including a III-V semiconductor substrate, a III-V semiconductor top layer and an etch stop layer sandwiched therebetween, the etch stop layer including aluminium and phosphorous; and etching through the top layer to the etch stop layer by use of a dry etch containing chlorine to provide two spaced apart recesses defining the optical waveguide therebetween.
1 .- 19 . (canceled)
20 . A method of manufacture of an optical waveguide structure comprising the steps of
providing a multilayer semiconductor wafer comprising a III-V semiconductor substrate, a III-V semiconductor top layer and an etch stop layer sandwiched therebetween, the etch stop layer comprising aluminum and phosphorous; and
etching through the top layer to the etch stop layer by use of a dry etch containing chlorine to provide two spaced apart recesses defining the optical waveguide therebetween.
21 . The method as claimed in claim 20 wherein the III-V semiconductor top layer comprises a plurality of III-V semiconductor layers.
22 . The method as claimed in claim 20 , wherein the III-V semiconductor top layer comprises at least one GaAs layer.
23 . The method as claimed in claim 20 , wherein the III-V semiconductor top layer comprises at least one AlGaAs layer, the AlGaAs layer preferably having the composition Al z Ga 1−z As where z is in the range 0.1 to 0.95.
24 . The method as claimed in claim 20 , wherein the dry etch is a chlorine containing precursor.
25 . The method as claimed in claim 24 wherein the chlorine containing precursor comprises chlorine gas.
26 . The method as claimed in claim 24 , wherein the chlorine containing precursor comprises BCl 3 .
27 . The method as claimed in claim 24 , wherein the chlorine containing precursor comprises CCl 4 .
28 - 37 . (canceled)
38 . A method as claimed in claim 23 , wherein z is in the range of about 0.2 to about 0.35.
39 . A method as claimed in claim 38 , wherein z is about 0.24.