Formation of Tantalum Carbide and Nitride Phases in Atomic Layer Deposition Using Hydrogen Plasma and tert-Butylimido-tris (diethylamido)-tantalum (TBTDET), and its Effect on Material Properties

Abstract

TaCN films are deposited with plasma-enhanced atomic layer deposition (PEALD) using tert-butylimido-tris(diethylamido)tantalum and hydrogen. It is confirmed that the film is a homogeneous mixture of TaC, TaN, Ta3N5, and Ta2O5 with the oxide phase formed from the post-deposition uptake of oxygen from the air. It is shown that the electrical properties of TaCN film are affected by the phase composition in the film. The effects of process parameters, such as deposition temperature, plasma power, and cycle time, on the film composition and electronic properties are evaluated. With the increase of the TaC and TaN phases over the Ta3N5 phase, the resistivity of the film is decreased. As the deposition temperature, plasma power, and plasma cycle time are increased, the carbide and TaN phases in the film are increased and the film resistivity is decreased. The uptake of oxygen after deposition is up to 10 at.-%, and the resistivity of TaCN film deposited using PEALD is as low as 350 mu Omega . cm.