Metalorganic vapour-phase epitaxial growth of red and infrared vertical-cavity surface-emitting laser diodes

Metalorganic vapour phase epitaxy (MOVPE) is used for the growth of vertical-cavity surface-emitting laser (VCSEL) diodes. MOVPE exhibits a number of important advantages over the more commonly used molecular beam epitaxial (MBE) techniques, including ease of continuous compositional and dopant grading for low-resistance p-type distributed Bragg reflectors (DBRs), higher growth rates for rapid throughput and greater versatility in choice of materials, especially with phosphorus, and dopants. Top-emitting InGaAs/AlGaAs/AlAs 950nm VCSELs exhibit the highest power conversion (wallplug) efficiencies (21%), lowest threshold voltage (1.47V), and highest single mode power (4.4 mW from an 8 μm device) yet reported. GaAs/ AlGaAs/AlAs VCSELs lasing near 850 nm have demonstrated record low threshold voltage (1.7V) at this wavelength, and excellent uniformity in wavelength (±1%) across a 3-inch wafer, and in threshold voltage (±1.5%), threshold current (±10%) and output power (±20%) across a 34-element array. 650 nm VCSELs based on AlGaInP/AlGaAs heterostructures have been demonstrated by MOVPE only, and lase continuous wave at room temperature, with voltage thresholds between 2.5 and 3 V and maximum power outputs of over 0.3 mW. These results establish MOVPE as a proven growth technique for this important new family of photonic devices.