Tracking the onset of defect in light emitting semiconductor devices via two-photon excitation microscopy and spectral microthermography

Abstract

We demonstrate a multi-functional optical technique to track and image the evolution of failure in a semiconductor device under real field conditions. A single optical platform is employed to acquire 3D photocurrent images and spectral reflectance maps of a 605 nm light emitting device (LED). We induce a device defect by electrical stress and observe microscopic stress patterns in the LED surface which are difficult to recognize with linear excitation and revealed only in 2P excitation. We also investigate the local thermal activity of the active region by measuring the corresponding changes in its spectral reflectance under different biased currents. Background-free thermal maps are then derived at optical resolution to establish the operational limits of the device and the correlation between structural defect and thermal activity in the active region.