Looks like its a bootstrap diode for a driver chip, needs to be fast or schottky and handle the full supply voltage - since schottkys aren't so good at high voltage I'd opt for ultrafast rectifier 1A rating or so. Or look up the datasheet for the particular driver ICs you have and see if it has information.
This is the original part
https://www.semicon.sanken-ele.co.jp/sk_content/sjpx-h3_ds_en.pdf
A 300V 2A FRED diode
4N03 is the date code
https://www.semicon.sanken-ele.co.jp/sk_content/sjpx-h3_ds_en.pdf
A 300V 2A FRED diode
4N03 is the date code