Platforms based on silicon photonic integrated circuits are expected to play an important role because of the availability of large diameter wafers and CMOS fabrication technology. However, the team notes that it is difficult to create light sources using silicon because it is an indirect bandgap semiconductor.
Now, Nobuhiko Nishiyama and his colleagues have demonstrated 1550nm GaInAsP lasers on silicon created using low temperature plasma activated bonding (PAB).
The hybrid wafers, which consist of an InP based wafer and a silicon on insulator wafer, were fabricated by PAB. After being irradiated with plasma in a vacuum chamber to active their surfaces, the two wafers were bonded at 150°C – said to be a much lower bonding temperature than used in conventional methods.
The hybrid lasers showed lasing operation at room temperature with a threshold current of 64mA, equating to a threshold current density of 850A/cm 2.
