Influence of near-surface graded-gap layers on electrical characteristics of MIS-structures based on MBE grown HgCdTe

The paper examines influence of near-surface graded-gap layers on electrical characteristics of MIS-structures fabricated on heteroepitaxial Hg(1-x)Cd(x)Te films grown by molecular beam epitaxy (MBE). Two types of insulators, i.e., two-layer SiO(2)/Si(3)N(4) and anodic oxide films were used. As it is seen from the depth and width of the valley on the C-V characteristics, the capacitance is found to vary in a wide range, in contrast to the structures without graded-gap layers. It is shown that the graded-gap layer under MIS-structures with x = 0.22 effectively reduces the tunnelling generation via deep levels and increases a lifetime of minority carriers in the space charge region and its differential resistance. The properties of the HgCdTe-insulator interfaces are studied.