Very high compositional homogeneity of 1.55 μm strain-compensated InGaAsP MQW structures by MOVPE under N 2 atmosphere

Abstract

In order to improve the compositional homogeneity in metalorganic vapor phase epitaxy (MOVPE), growth under N 2 used as carrier gas has been applied for the first time to strain-compensated InGaAsP multi-quantum-well (MQW) structures on InP. Various InGaAs(P) layers and MQW structures have been grown by low-pressure MOVPE in a horizontal reactor at total gas flows Q tot=3.0–7.6 slm with substrate rotation using standard precursors. By replacing H 2 by N 2 the lateral homogeneities of the gap wavelength, lattice mismatch and layer thickness were considerably improved. The role of the carrier gas is discussed. The standard deviation σ(λ) of the wavelength over 40 mm of a 50 mm wafer of strain-compensated λ=1.55 μm laser structures with 10 QWs was reduced from 6.5 nm (H 2) to 0.55 nm (N 2), which is a factor of about 10! This is one of the best homogeneity values reported so far for InGaAsP grown in any type of MOVPE reactor with any precursors. Details of the growth parameters and results are presented along with the characteristics of distributed feedback (DFB) lasers and laser arrays produced from these structures.