SUBMOUNT AND SEMICONDUCTOR DEVICE

摘要

A submount on which a semiconductor light emitting device is mounted with a high bonding strength. The submount (3) comprises a substrate (4) and a solder layer (8) formed on a main surface (4f) of the substrate (4). The density of the solder layer (8) is not less than 50% and not more than 99.9% of the theoretical density of the material that constitutes the solder layer (8). The solder layer (8) comprises at least one kind selected from the group consisting of gold-tin alloys, silver-tin alloys and lead-tin alloys. Before fusion, the solder layer (8) is formed on the substrate (4) and comprises an Ag film (8b) and an Sn film (8a) provided on the Ag film (8b). The submount (3) further comprises an Au film (6), which is formed between the substrate (4) and the solder layer (8).