New chemical solutions for the etching of (011) oriented V- grooves in InP(001) for CSBH laser diodes.

We have developed two new etchant systems by adding H sub 2 O sub 2 and HBr into the conventional HCl-H sub 3 PO sub 4 etchant for the fabrication of InP-based channelled substrate heterostructure (CSBH) lasers. These etchants do not erode photoresists and they provide high quality etched side walls. The etch factors for the new etchant systems based on HBr and H sub 2 O sub 2 are 17% and 12% higher than that of the conventional 5HCl-H sub 3 PO sub 4 etchant respectively. These high etch factors give a narrow V-groove in InP and they lead to a better control of the threshold current and fundamental transverse mode operation of CSBH lasers.