Bonding pad induced stresses in (Al,Ga)As double heterostructure lasers

Abstract
We have studied Au bonding pad induced stresses in (AlGa)As double heterostructure lasers by photoluminescence, x-ray Automatic Bragg Angle Control measurements, and infrared and optical microscopy. Examination of several devices which have thick (10–12 μm) plated Au bonding pads indicates that stresses approaching the fracture stress can exist in such devices. The high stress induces aggregates of microcracks along 〈100〉 directions in the epitaxial layers. Regions in the stripe where the cracks intersect are nonradiative, causing failure of the device.