Effects of low-temperature (≈500°C) microwave annealing (MWA) of Cluster-Carbon (C7) and Phosphorus implants are compared with rapid thermal annealing (RTA) at 900 and 1000°C for (100) and (110)-Si substrates. MWA annealing resulted in high levels of substitutional Carbon, 1.57% for (100)Si and 0.99% for (110)Si for C7 implants. Addition of high-dose Phosphorus implants resulted in lower but still useful substitutional Carbon levels, 1.44% for (100)Si and 0.68% for (110)Si after MWA. RTA annealing at higher temperatures resulted in greatly reduced substitutional Carbon levels and deeper Phosphorus junctions. The effects of subsequent anneals by MWA and RTA methods are reported. MWA is shown to be a promising method for high-channel tensile strain in nMOSFETs with a substantially lower thermal budget than RTA.