Patent ID: 10989755

Abstract:
Embodiments relate to functional test methods useful for fabricating products containing Light Emitting Diode (LED) structures. In particular, LED arrays are functionally tested by injecting current via a displacement current coupling device using a field plate comprising of an electrode and insulator placed in close proximity to the LED array. A controlled voltage waveform is then applied to the field plate electrode to excite the LED devices in parallel for high-throughput. A camera records the individual light emission resulting from the electrical excitation to yield a function test of a plurality of LED devices. Changing the voltage conditions can excite the LEDs at differing current density levels to functionally measure external quantum efficiency and other important device functional parameters. Spectral filtering is used to improve measurement contrast and LED defect detection. External light irradiation is used to excite the LED array and improve onset of charge injection light emission and throughput.