Plasma doping of high aspect ratio structures

Doping high aspect ratio (HAR) structures poses a major challenge for device manufacturers, particularly in the advanced memory and CMOS image sensor technology spaces. CMOS technology scaling limitations have led to the emergence of vertically integrated cells, which leading-edge chipmakers are already introducing into mass production. Each case involves HAR structures that may require doping to improve or even enable device operation. Meanwhile, scaling is driving CMOS image sensor device challenges in pixel-to-pixel isolation, dark-current reduction, and noise reduction. This study demonstrates the capability of plasma doping as an enabling technology for doping in these challenging HAR structures. Plasma doping process flow optimization and analytical techniques, such as secondary ion mass spectroscopy (SIMS), are demonstrated.