AUTOMATED INSTALLATION OF DIAGNOSTICS OF QUALITY OF LIGHT-EMITTING HETEROSTRUCTURES BY THE METHOD OF DYNAMIC PHOTOELECTRIC RESPONSE
The block diagram and the principle of action of the automated installation for diagnostics of lateral uniformity of light-emitting heterostructures with quantum walls by measurement and the analysis of a photoelectric response (photovoltage or a photocurrent) are considered at their local dynamic photoexcitation the narrow-band optical radiation of a visible band. The possibility of the choice of harmonic or pulse modulation of counting rate of a flare with adjustment of parameters of modulation is provided in the installation. The electronic-mechanical and optical systems of positioning operated by the microcontroller provide a flare of the heterostructures with quantum walls local area with a minimum diameter of spot of 30 microns and accuracy of positioning ±10 microns. The data acquisition module LA-N1USB transforms a photoresponse signal to a digital signal and transfers it to the computer for processing. Results of approbation of a method and installation on InGaN/GaN light-emitting diodes in the static mode confirm existence of inhomogeneities in distribution of a photoelectric on a light-emitting diode crystal surface. The developed method and installation can be used for diagnostics of quality of both light-emitting heterostructures with quantum walls, and other classes of semiconductor devices with p-n transitions: transistors, solar elements, photo diodes, etc.