NanoLEDs for next generation of ChipScope microscope ready
The optical resolution of the ChipScope microscope is defined by the size and distance of individually addressable LEDs underneath the specimen. In the final phase of the ChipScope project, the team of researchers from TUBS has realized nanoLED arrays with emitters down to 200 nm size, which will bring resolution close to the diffraction limit. The arrays are based on a direct-addressing scheme, providing two different shapes of 2×32 or 6×6 pixels, respectively.
The challenging fabrication of those nano-structured GaN-LED arrays was conducted with the assistance of the PTB in Braunschweig, where electron beam lithography was used for pattern definition. The remaining processing steps were done in the cleanroom facilities of TUBS. Currently, the performance of the new generation of microscopes equipped with those nanoLED-arrays is tested at AIT.
Images of different NanoLED arrays. Top row: scanning electron microscope images showing precise alignment of the contacts. Bottom row: optical microscope, revealing that the point of light emission can be shifted by driving electrical current through different wires. Note that the LED array itself is too small to fully resolve it in an optical microscope, even with highest magnification.