Charge distribution and electrical dipole in an Al2O3/4H-SiC structure are investigated by capacitance–voltage measurement and x-ray photoelectron spectroscopy (XPS). The charge densities in Al2O3 and at the Al2O3/4H-SiC interface are negligible and  −6.89  ×  1011 cm−2, respectively. Thus the small charge amount indicates the suitability of Al2O3 as a gate dielectric. The dipole at the Al2O3/4H-SiC interface is  −0.3 to  −0.91 V. The XPS manifests electron transfer from Al2O3 to 4H-SiC. The dipole formation is explained by a gap state model and the higher charge neutrality level of Al2O3 than the Fermi level of 4H-SiC, which confirms the feasibility of the gap state model on investigating band lineup at heterojunctions. The electrical dipole at the Al2O3/4H-SiC interface is critical for threshold voltage tuning. These results are helpful in engineering the SiC based gate stacks.
Keywords:Al2O3/4H-SiC,
Source:  iopscience

If you need more information about SiC 4H, please visit our website:www.qualitymaterial.net, and send us email at send us email at angel.ye@powerwaywafer.com or powerwaymaterial@gmail.com.