Room-Temperature Bonding of Vertical-Cavity Surface-Emitting Laser Chips on Si Substrates Using Au Microbumps in Ambient Air

The feasibility of room-temperature (RT) bonding of vertical-cavity surface-emitting laser (VCSEL) chips on silicon (Si) substrates with Au microbumps was demonstrated by Au-Au surface-activated bonding. The diameter at the top, the height, and the pitch of Au microbumps measured approximately 5, 2, and 10 mu m, respectively. Following activation of the Au surfaces with argon radio-frequency plasma, Au-Au bonding was carried out using contact at RT in ambient air. The measured results of light-current-voltage (L-I-V) characteristics indicated no significant degradation of the VCSEL chips after bonding. (C) 2008 The Japan Society of Applied Physics