Method of manufacturing semiconductor optical device and intermediate article of semiconductor optical device

A method of manufacturing a semiconductor optical device comprising the steps of:

• forming an etch stop layer on an InP growth substrate, the etch stop layer having a thickness of 5 nm or more and 50 nm or less;
• and
• forming a semiconductor laminate on the etch stop layer by stacking a plurality of InGaAsP-based III-V group compound semiconductor layers comprising at least In and P;
• bonding a support substrate to the semiconductor laminate having at least a metal bonding layer interposed therebetween;
• and
• removing the InP growth substrate,
• wherein the etch stop layer has a composition expressed by a formula InzGa(1-z)As, where In composition ratio z is more than 0.532 and 0.60 or less,
• the semiconductor optical device is a semiconductor light-emitting element having an emission peak wavelength in a range of 1000 nm to 2200 nm, and emits light from the surface opposite to the support substrate,
• the semiconductor laminate comprises an n-type cladding layer, an active layer, and a p-type cladding layer, in this order, and
• the p-type cladding layer has a thickness of 2400 nm to 9000 nm.