Silicon Nitride with Low Carbon Concentration Deposited by Radical Beam Deposition Technique with Organic Liquid Source

Abstract

Silicon nitride (SiN_x) films have been deposited at a substrate temperature ranged from R. T. to 800°C by a new radical-beam deposition technique. In order to reduce carbon incorporation into the film, hexamethyldisilazane was decomposed in a reaction with atomic nitrogen rather than in plasma directly in this technique. The carbon concentration of the film was estimated to be less than the order of 10¹⁹cm^-3 based on secondary ion mass spectroscopy. The density of the film estimated from Rutherford backscattering spectroscopy (RBS) increased from 2.6 to 3.2g/cm³ with increasing substrate temperature. The resistivity and the dielectric constant of the film were evaluated to be 10¹³Ω·cm at 3MV/cm and 5.7 at 300kHz, respectively. This new technique is promising to obtain high-quality SiN_x film by deposition without using SiH₄.