Excimer Laser Dopant Activation for Monolithic 3D Integration

Monolithic 3D (M3D) integration is a promising technology that allows for the vertical stacking of devices, offering significant improvements in device density and performance. One of the key challenges in M3D integration is the precise activation of dopants in the upper silicon (Si) layer without affecting the underlying layers.<br/>In this study, we investigate the feasibility of using excimer laser annealing (ELA) to activate dopants in the upper Si layer for future M3D integration. Our results demonstrate successful dopant activation in the upper Si layer, verified through sheet resistance measurements and secondary ion mass spectrometry (SIMS). The excimer laser's ultra-short pulse duration enables localized heating, thereby preventing thermal diffusion to the lower layers, a critical requirement for M3D integration.<br/>Although this study primarily focuses on dopant activation in the upper Si layer, these results provide valuable insights into the potential of excimer laser annealing as a key enabler for the subsequent steps in M3D integration. Further research will explore full device integration and the effects on stacked layers.