Effect of roughness of hydrogenated Si(111) surfaces on defect annealing and formation under excimer laser irradiation

Laser processing is a powerful tool for modification of semiconductor surfa ces and thin films [1]. Hydrogenated Si surfaces are important for ultracle an technology. However, the influence of intensive laser irradiation on the electronic properties of these surfaces has not been investigated yet. We have observed an annealing of nonradiative defects on hydrogenated Si(lll) surfaces with a roughness on the scale of interatomic distance and a decrea se of the threshold of laser induced defect formation for higher roughness after XeCl laser irradiation with pulse energies between 0.25 and 0.6 J/cm( 2) and 0.5 and 0.75 J/cm(2), respectively.