Study of phosphorus-doped Si annealed by a multi-wavelength laser

Abstract

Activation annealing of phosphorus (P)-doped Si was performed with a red–greenblue (RGB) laser to evaluate its potential for the uniform heating of patterned semiconductor devices. Various characteristics of P-doped Si annealed by an RGB laser were experimentally investigated. In addition, a numerical simulation of the multi-wavelength laser annealing process was conducted to predict the temperature distribution during the process. The electrical and crystalline properties were significantly affected by the laser power. Additionally, the wavelength combination considerably affected the electrical and crystalline characteristics under moderate laser powers (27–28 W). However, the effects of the laser power and wavelength on the atomic structure were negligible. Substantial P redistribution and an increase in the surface roughness were only observed for the highest laser power (30 W) using the RGB wavelength, resulting in the highest temperature (∼2076 K) in the simulation. Under this condition, complete melting beyond end-of-range defect zone occurred, leading to a full epitaxial growth of Si and a very low sheet resistance. According to the simulation results, for the same laser power, the RGB wavelength exhibited a higher temperature than the RB wavelength because of the high absorption rate of the green laser in Si.

Keywords

• Laser annealing
• Activation
• Multi-wavelength laser
• Numerical simulation
• Temperature distribution