Semiconductor materials are fundamental materials in all modern electronic devices. Continuous demand for faster and more energy-efficient electronics is pushing miniaturization and scaling to unprecedented levels. Controlled and uniform doping of semiconductor materials with atomic accuracy is critical to materials and device performance. In particular, junction depth and dopant concentration need to be tightly controlled to minimize contact resistance, as well as variability effects due to random dopant fluctuations in the channel. Conventional doping methods such as ion implantation is imprecise and can have large variability effect. Moreover, energetic introduction of dopant species will often cause crystal damage, leading to incompatibility with nanostructured-materials and further performance degradation. To address these problems, researchers at the University of California, Berkeley, have experimented with an alternative approach to a wafer-scale surface doping technique first developed at the UC Berkeley in 2007. The team has demonstrated a controlled approach for monolayer doping (MLD) in which gas phase dopant-containing molecules form low-variability, self-assembled monolayers (SAM) on target semiconductor surfaces.
semiconductor, doping, monolayer doping, MLD, gas phase, ultrashallow junctions, USJ