Chemical vapor deposition and characterization of phosphorus nitride (P3N5) gate insulators for InP metal-insulator-semiconductor devices

Abstract

A new gate insulating film consisting of P₃N₅ was formed on an InP surface by a new chemical vapor deposition (CVD) technique. A suitable combination of reagents (PH₃ and NH₃) made P₃N₅ CVD feasible in an ambient free from oxygen and having excess phosphorus pressure. The new insulator revealed ohmic conduction with a resistivity as high as 10⁴Ω cm. The breakdown field intensity increased up to 10⁷V/cm at room temperature. The low frequency dielectric constant was 3.7 ε₀. A very minor hysteresis was seen in the capacitance‐voltage curves measured on P₃N₅‐ InP metal‐insulator‐semiconductor diode. The interface state density was reduced to 10¹²/cm²eV at an energy near the conduction band edge. Photoluminescence spectra were measured before and after CVD to determine the surface passivation effect.