Heteroepitaxial growth of TaN on MgO(001) and TiN(001)/Si(001) by pulsed laser deposition

ABSTRACTEpitaxial TaN(001) films have been successfully grown on MgO(001) single crystal and TiN(001) buffered Si(001) substrates by pulsed laser deposition method. Crystalline TaN layers of about 100 nm thick were deposited under a base pressure of 5 × 10−6 Torr and at substrate temperatures ranging from 500°C to 700°C. X-ray diffraction results suggested that stoichiometric TaN films with cube-on-cube <001>TaN∥<001>MgO heteroepitaxy are obtained in this temperature range. Plan-view and cross-sectional electron microscopy analysis revealed excellent structural quality and sharp interface boundary. TaN films grown on TiN(001) buffered Si(001), however, showed a mixture of TaNx (with x ≤ 1) components. Although the (001)-orientated TaN is always present prominently, the nitrogen deficient TaNx components are often co-existed in the films and show up as a broad peak in the X-ray diffraction profile. Stoichiometric and single phase TaN(001) films can only be obtained in a narrow temperature window at around 550oC and heteroepitaxial relation <001>TaN∥<001>TiN∥<001>Si has been demonstrated.