Electrical properties of metal-insulator-semiconductor structures with silicon nitride dielectrics deposited by low temperature plasma enhanced chemical vapor deposition distributed electron cyclotron resonance

The present article reports a study of current-voltage (J-E) and capacitance-voltage (C-V) measurements on metal-insulator-semiconductor diodes, using SiNx:H as an insulator layer and Si or InP as semiconductors. We have deposited SiNx:H films by distributed electron cyclotron resonance plasma enhanced chemical vapor deposition at floating temperature, with physical properties similar to films prepared at 800 degrees C by low pressure chemical vapor deposition. Silane and nitrogen were used as the reactive gases. The experimental results show that the resistivity (rho) and the critical field (E-C) are a strong function of the dielectric composition. For films deposited under optimum conditions, rho was equal to 10(16) Ohm cm and E-C reached 3.65 or 4.5 MV/cm for Al/SiNx:H/Si and Al/SiNx:H/InP diodes, respectively. The dominant mode of electronic conduction appears to be the Poole-Frenkel emission. The postmetallization annealing (PMA) has no significant effect on these bulk properties (rho, E-C and electronic conduction). On the contrary, PMA has been shown to mainly affect the properties of both SiNx:H/Si and SiNx:H/InP interfaces. The optimized Al/SiNx:H/Si fabrication procedure induced a midgap interface state density (D-it) of 6 X 10(10) eV(-1) cm(-2) evaluated by high frequency and quasistatic C-V characteristics. In the case of Al/SiNx:H/InP diodes, we have found that the carrier trapping by direct tunneling near the SiNx:H/InP interface is dominant. (C) 1997 American Vacuum Society. [S0734-2101(97)04406-0].