Deepak Ramappa

Ion-implant doped large-area n-type Czochralski high-efficiency industrial solar cells

This paper discusses the design and fabrication of ion-implanted, high-efficiency, light-stable, 156 mm square, screen-printed solar cells on n-type Czochralski (Cz) silicon with full industrial processing. Doping by ion implantation provides a significant advantage over conventional furnace-based doping by providing uniform, full-area emitter and back-surface field (BSF) regions, and can eliminate four process steps over the conventional n-type cell process. Low emitter saturation current density (Joe) values of 50 fA/cm2 were achieved on boron implanted test structures passivated by an in-situ thermal oxide. Complete solar cells were fabricated with high values of short-circuit current density (Jsc), which is attributed to high lifetime of n-type base and also a superior phosphorous BSF compared to the conventional aluminum BSF (Al-BSF).

Benefits of Damage Engineering for PMOS Junction Stability

As CMOS devices continue to shrink, the formation of ultra shallow junction (USJ) in the source/drain extension remains to be a key challenge requiring high dopant activation, shallow dopant profile and abrupt junctions. The next generations of sub nano‐CMOS devices impose a new set of challenges such as elimination of residual defects resulting in higher leakage, difficulty to control lateral diffusion, junction stability post anneal and junction formation in new materials. To address these challenges for advanced technological nodes beyond 32 nm, it is imperative to explore novel species and techniques. Molecular species such as Carborane (C2B10H12), a novel doping species and a promising alternative to monomer Boron is of considerable interest due to the performance boost for 22 nm low power and high performance devices. Also, to reduce residual defects, damage engineering methodologies have generated a lot of attention as it has demonstrated significant benefits in device performance. Varian proprieta...