Indium phosphide substrate and method for producing indium phosphide substrate

A method for producing an indium phosphide substrate, comprising the steps of:

• grinding an ingot of indium phosphide at a grinding wheel feed rate of 20 to 35 mm/min using a grinding wheel having a grit size of #270 to #400 to form an orientation flat;
• cutting out at least one wafer having a main surface and an orientation flat from the ground ingot of indium phosphide;
• chamfering an outer circumference portion of the wafer other than end faces of forming the orientation flat;
• polishing at least one surface of the chamfered wafer;
• and
• etching the polished wafer under the following etching conditions:
• etching conditions:
• (Composition of Etching Solution)
• when the composition comprises 85% by mass of aqueous phosphoric acid solution and 30% by mass of hydrogen peroxide solution, the composition has a volume ratio of the aqueous phosphoric acid solution:
• the hydrogen peroxide of 0.2 to 0.4:0.1, the balance being water so as to add up to 1 as the total etching solution;
• (Temperature of Etching Solution)
• from 60 to 100° C.;
• (Etching Time)
• from 8 to 15 minutes.

A method for producing an indium phosphide substrate, comprising the steps of:

• grinding an ingot of indium phosphide to form an orientation flat;
• cutting out at least one wafer having a main surface and an orientation flat from the ground ingot of indium phosphide;
• griding end faces of the orientation flat on the wafer at a grinding wheel feed rate of 60 to 180 mm/min using a grinding wheel having a grit size of #800 to #1200 and chamfering an outer circumference portion other than the orientation flat;
• polishing at least one surface of the chamfered wafer;
• and
• etching the polished wafer under the following etching conditions:
• etching conditions:
• (Composition of Etching Solution)
• when the composition comprises 85% by mass of aqueous phosphoric acid solution and 30% by mass of hydrogen peroxide solution, the composition has a volume ratio of the aqueous phosphoric acid solution:
• the hydrogen peroxide of 0.2 to 0.4:0.1, the balance being water so as to add up to 1 as the total etching solution;
• (Temperature of Etching Solution)
• from 60 to 100° C.;
• (Etching Time)
• from 8 to 15 minutes.