Excimer laser doping using solid diffusion source is investigated. By using Al thin films deposited on n-type Si substrates as the diffusion source, p-type regions are formed on the surfaces of the n-type Si substrates after laser irradiation. The diode characteristics as well as the surface roughness show that pn junctions showing good rectifying characteristics without surface roughening are obtained by optimization of the laser fluence. The peak Al concentration is much higher than the solubility limit under thermal equilibrium conditions, suggesting the irradiation-enhanced diffusion. This technique will be useful to fabricate advanced devices for next-generation electronics with low thermal budget.