Single run etching and regrowth of InP/GaInAsP by GSMBE

We report for the first time the successful etching of InP/GaInAsP heterostructures by the chemical beam etching technique using PCl₃ , and on the combination of this etching technique with regrowth using standard GSMBE conditions. The kinetics of etching have been studied over a large temperature range. The difference in etch rates between InP and GaInAsP is explained by a difference in the group III chloride stoichiometry (InCl, GaCl₃). This difference leads probably to a modification of the surface composition during etching, the surface becoming richer in Ga. The dopants (Si, Be) are found to accumulate at the etch/regrown interface. The silicon atoms are not removed and create a δ-doped layer at the regrowth interface, The surface morphology of etched samples have been improved by etching at low temperature, in agreement with the RHEED observations showing a smooth 2D layer by layer etching mode in this case. In particular, the decoration of dislocations observed after etching at high temperature is not found on low temperature etched samples. This low temperature etching procedure is well adapted to the regrowth of high quality InP/GaInAsP structures