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 SiN_x:H as an insulator layer and Si or InP as semiconductors. We have deposited SiN_x:H films by distributed electron cyclotron resonance plasma enhanced chemical vapor deposition at floating temperature, with physical properties similar to films prepared at 800 °C by low pressure chemical vapor deposition. Silane and nitrogen were used as the reactive gases. The experimental results show that the resistivity (ρ) and the critical field (E_C) are a strong function of the dielectric composition. For films deposited under optimum conditions, ρ was equal to 10¹⁶ Ω cm and E_C reached 3.65 or 4.5 MV/cm for Al/SiN_x:H/Si and Al/SiN_x: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 (ρ, E_C and electronic conduction). On the contrary, PMA has been shown to mainly affect the properties of both SiN_x:H/Si and SiN_x:H/InP interfaces. The optimized Al/SiN_x:H/Si fabrication procedure induced a midgap interface state density (D_it) of 6×1- - 0¹⁰ eV^-1 cm^-2 evaluated by high frequency and quasistatic C–V characteristics. In the case of Al/SiN_x:H/InP diodes, we have found that the carrier trapping by direct tunneling near the SiN_x:H/InP interface is dominant. © 1997 American Vacuum Society.