ELECTRICAL BEHAVIOR OF EPITAXIAL SRF2 INP(100) DIODES/

In this paper, it is shown that the conductivity of SrF2 layers epitax ially grown onto n-type InP(100) substrates is about 10(-16) S cm(-1) at room temperature with an activation energy close to 0.7 eV. An ioni c contribution only appears for temperatures higher than 380 K. The el ectrical properties of MIS structures (metal/SrF2/n-type InP(100)) wer e investigated by means of capacitance-voltage characteristics (C(V)) and admittance spectroscopy measurements. The results strongly depend on the cleaning process applied to the semiconductor surface. The clas sical cleaning process (H2SO4.H2O2.H2O+HF deoxidization) did not allow the accumulation regime to be reached in the semiconductor. In this c ase the trap density is greater than 10(12) eV(-1) cm(-2). On the othe r hand, it was demonstrated that treatment with ammonium sulphide impr oves the qualities of the device. In particular, the density of states can be reduced to 10(11) eV(-1) cm(-2) and the accumulation regime is achieved.