Good quality Al/SiNx : H/InP metal-insulator-semiconductor devices obtained with electron cyclotron resonance plasma method

Abstract

We have obtained Al/SiNx:H/InP metal-insulator-semiconductor devices depositing SiNx:H thin films by the electron cyclotron resonance plasma method at 200 degrees C. The electrical properties of the structures were analyzed according to capacitance-voltage and deep level transient spectroscopy measurements. We deduce an inverse correlation between the insulator composition-the N/Si ratio-and the density of interface traps: those films with the maximum N/Si ratio (1.49) produce devices with the minimum trap density-2 x 10(12) cm(-2) eV(-1) at 0.42 eV. above the midgap. We explain the influence of film composition on the interface trap density in terms of a substitution of phosphorous vacancies at the InP surface, V-p, by N atoms coming from the insulator, N-Vp. The values obtained in our research for the interface trap distribution were similar to other published results for devices that use chemical and/or physical passivation processes of the InP surface prior to the deposition of the insulator.