Impact of phosphorus implantation on the electrical properties of SiO2/4H-SiC interfaces annealed in N2O

In this work, the combined effect of a shallow phosphorus (P) pre-implantation and of a nitridation annealing in N2O on the properties of the SiO2/4H-SiC interface has been investigated. The peak carrier concentration and depth extension of the electrically active dopants introduced by the nitridation and by the combination of P pre-implantation and nitridation were determined by high resolution scanning capacitance microscopy (SCM). Macroscopic capacitance-voltage (C-V) measurements on metal oxide semiconductor (MOS) capacitors and nanoscale C-V analyses by SCM allowed to quantify the electrical effect of the donors introduced underneath the SiO2/4H-SiC interface. Phosphorous pre-implantation and subsequent high temperature electrical activation has been shown not only to produce an increased doping in the 4H-SiC surface region but also a better homogeneity of surface potential with respect to the use of N2O annealing only.