An integrated circuit includes a first polysilicon region having a first grain size formed on a substrate. The integrated circuit also includes a second polysilicon region, having a second grain size different from the first grain size, formed on the substrate. Furthermore, a method of fabricating an integrated circuit is also provided. The method includes forming a first polysilicon region having an initial grain size on a substrate. The first polysilicon region is implanted with a first dopant of a first conductivity type and a second dopant. After the implantation, the first polysilicon region has a first grain size larger than the initial grain size. Then, a laser rapid thermal annealing process is performed to the first polysilicon region.