• Sagazan, Olivier De
• Levallois, Christophe
• Chevalier, Nicolas
• Taleb, Fethallah
• Pes, Salvatore
• Alouini, Mehdi
• Folliot, Hervé
• Paranthoen, Cyril

Abstract

The development of power efficient vertical-cavity surface-emitting lasers (VCSELs) in the 1.55µm range, with relatively high output power (>1mW) and enhanced thermal dissipation is still challenging, but would represent a real breakthrough for the scientific community, with important perspectives in different areas of fundamental research and applied physics (WDM and FTTH networks, gas sensing and deformation detectors, microwaves, etc.). In this context, a novel bonding technique is presented in this work. It relies on the use of a BCB polymer bonding to virtually report any material on a Si host platform, through the use of Cu-filled vias acting as µ-heat sinks. This so-called Through Silicon Holes Electroplated Copper (TSHEC) technique has undoubtedly several advantages, since it allows a hybrid integration of III-V active regions on a Si substrate (for photonics, microelectronics, microfluidics integration), it avoids stress-induced limitation with respect of standard large Cu surface solutions, and it is cost-effective. Moreover, it is fully compatible with optical pumping as well as electrical injection schemes. This approach has been recently validated in the case of InP-based OP-VCSEL structures, for which an emission power exceeding 2mW with a threshold as low as 7mW at 20°C has been demonstrated, in the case of a bottom hybrid metal-dielectric Bragg mirror (H-DBR) of 20µm in diameter. Different diameter sizes for the bottom H-DBR have been tested, ranging from 20µm up to 100µm. According to the size of the H-DBR, different values for the output power have been measured, together with a red shift of the laser emission, which are related to different values for the thermal impedance of the devices.

Topics

• impedance spectroscopy
• surface
• polymer
• copper
• Silicon