SUBSTRATE FOR OPTICAL SEMICONDUCTOR

摘要

A substrate for optical semiconductors of the present invention comprises an insulating ceramic substrate, a metal layer provided on the insulating ceramic substrate, a solder layer provided on the metal layer and composed of Sn only or 50 wt % or more of Sn and the balance substantially of Au, and a protective layer provided on the solder layer and composed of Au or Ag having a thickness of 0.01 mum or more and 1 mum or less. The substrate for optical semiconductors as described above makes it possible to reduce stress placed on the optical semiconductor, to suppress development of crystal defects, and to prolong its life when joining the optical semiconductor easily developing crystal defects by slight stress or when in use thereafter.