RAPID FORMATION OF ARSENIC-DOPED LAYER MORE THAN 1.0 MU-M DEEP IN SI USING 2 KRF EXCIMER LASERS

Sequential irradiation by two KrF excimer lasers (lambda=248 nm) has b een used to activate arsenic atoms implanted into Si substrates. The 1 st laser pulse having 34 ns pulse width followed by the 2nd laser puls e of 23 ns after a time delay was irradiated to the sample. Laser flue nces of the 1st laser pulse and the 2nd laser pulse were set at 2.4J/c m(2) and 0.5J/cm(2), respectively. The substrate was heated to 700 deg rees C, From Rutherford backscattering spectroscopy (RBS) analysis, th e depth of the doped layer is confirmed to be 1.0 mu m. Severely rippl ed surface was observed by atomic force microscope (AFM) for the sampl e irradiated without tile 2nd laser pulse, but tile surface morphology can be improved by tile sequential irradiation of two pulses. For a t ime delay of 150 ns, the minimum values of X(min) (4.61%) and sheet re sistance (41.43 Omega/rectangle) were obtained.