Effect of channeling of halo ion implantation on threshold voltage shift of metal oxide semiconductor field-effect transistor

Abstract

In this letter, we report threshold voltage shift of metal oxide semiconductor field effect transistor (MOSFET) after the halo ion implantation process. Although halo implantation can significantly reduce the short channel effect, it causes a threshold voltage shift of a long channel device due to dopant channeling through polycrystalline silicon grain boundary. Although the chemical vapor deposited (CVD) cap oxide on polycrystalline silicon gate was used as a blocking layer of dopant, threshold voltages shift clearly indicate dopant channeling through polycrystalline silicon. To avoid a channeling problem, a thicker cap oxide layer or lower halo implantation energy is necessary.