High intensity electron field emissions were obtained from SiC/Si heterostructures formed by high temperature carbon implantation into silicon and subsequently etching of the top silicon layer. Implantation processes were performed at 700 °C with a dose of 3.0 to 8.0 x 1017 ions/cm2. Post-implantation annealing in argon at 1250 °C for 5h was done for partial samples. β-SiC precipitates were easily formed and embedded in silicon at the interface of SiC/Si heterostructures during high temperature carbon implantation for all samples. The densely distributed small protrusions led to efficient electron emission. Implantation dose scarcely impacted the electron emission characteristics when it reached to a definite value. After annealing, the density of protrusions at the interface of SiC/Si heterostructures became smaller since β-SiC precipitates were grown into larger sizes, which caused to a relatively inefficient electron emission.