The role of а buffer layer at the contact with silicon in structures with an insulating gap made of a material replacing SiO2

The shape of high -frequency capacitance -voltage characteristics of structures with an insulating layer replacing silicon oxide is considered. It is shown that the buffer layer interaction on the interface with silicon substrates is related to the shielding of external electric fields by charges of the electron traps. It is found that the presence of two plateaus in the high -frequency capacitance -voltage characteristics does not necessarily indicate deep depletion and strong enrichment of a semiconductor. The presence of both capacitive plateaus in the case of strong screening can be explained by the pinning of the Fermi level of Si on electron traps of the buffer layer with a high concentration and a U-shaped spectrum. An algorithm is formulated for calculating the band bending in a semiconductor from the minimal values of the high -frequency capacitance of a sample in the region of depletion effects on the substrate. The theoretical construction was used for determining the characteristics of a structure with an insulating HfO2 layer and it was shown that in this case the buffer layer almost completely shields external electric fields, which prevents significant band bending in the silicon substrate.