Electrical properties of Si-N films deposited on silicon from reactive plasma

Abstract

Because reactive‐plasma‐deposited Si‐N films might offer certain advantages in silicon integrated‐circuit technology, we have evaluated their electrical properties and compared them with those of CVD Si₃N₄. Various films with compositions in the range 0.75?Si/N?1.9 were studied using C‐V and I‐V measurements, the latter at temperatures up to 200 °C. The dominant conduction mode appears to be Frenkel‐Poole emission; this is consistent with the observed linear I‐vs‐V^1/2 relationship and magnitudes of various parameters. The resistivities (range 10⁴–10²¹ Ω cm at 2×10⁶ V/cm) and dielectric strengths (range 0.8×10⁶ to 8×10⁶ V/cm) are found to depend upon the film composition and on an as yet undefined structural parameter (for Si/N?0.75). The interface between Si‐N and Si is associated with a high density of surface charge (≳10¹² cm⁻²) and a large trapping instability.