Patent ID: 7575986

Claim:
A method of making a transistor on a semiconductor substrate, comprising: forming a gate dielectric on said semiconductor substrate; forming a gate electrode on the gate dielectric; ion implanting dopant impurities into said semiconductor substrate to form source and drain regions including ultra-shallow source and drain extensions; performing millisecond laser annealing by scanning a laser-generated light beam across said semiconductor substrate so as to raise each region illuminated by said light beam to a peak temperature at or near a melting temperature of material of said semiconductor substrate; and prior to said ion implanting dopant impurities to form said source and drain regions, raising the temperature of said semiconductor substrate from an ambient temperature to said peak temperature of said millisecond laser annealing at a first rate and decreasing the temperature of said semiconductor substrate from said peak temperature to an ambient temperature at a second rate, said first and second rates being less than 250 degrees C. per second.