Alfred Mak

TiCN: A new chemical vapor deposited contact barrier metallization for submicron devices

High‐quality chemical vapor deposited TiCN films were produced in a single wafer reactor using a metallorganic (TDMAT) precursor. The films have excellent step coverage over high aspect‐ratio contacts as well as very low particle content. These properties are obtained because the films are deposited under surface‐reaction controlled conditions. The films show also excellent barrier properties against Al and WF6 attack. These properties make this material a superb contact barrier material for ultra‐large‐scale integrated devices.

Characterization of a PECVD WxN process using N2, H2, and WF6

Abstract A novel plasma-enhanced chemical vapor deposition (PECVD) tungsten nitride (WxN) process was developed on an Applied Materials Centura™ W×Z chamber. Nitrogen (N2), hydrogen (H2), and tungsten hexafluoride (WF6) are the active components for this PECVD process. Si substrate encroachment by WF6 can be suppressed by a N2/H2 plasma pretreatment before WxN deposition. Resistivity of WxN film decreases as H2/WF6 ratio increases and deposition temperature rises. A metrology technique using ellipsometry was used to measure the index of refraction and absorption coefficient to quantify WxN thickness and stoichiometry. Depending on W to N ratio and process conditions, the index of refraction, n, at 433 nm was measured between 3.26 and 3.68 and the absorption coefficient between 2.14 and 3.14. The resistivity of WxN with x=0.7–2.2 was measured between 1850 and 240 μΩ cm on an as-deposited film. Step coverage, surface roughness, stress, and impurity content of the amorphous films will also be reported. Feasibility of the in situ W/WxN stack deposition will be presented with the results to demonstrate the capability for gate stack application.

Effect of NH3 thermal treatment on an atomic layer deposited on tungsten films and formation of W–B–N

The effect of ammonia (NH3) ambient annealing on a tungsten (W) film deposited by atomic layer deposition at temperatures ranging from 400–700 °C is discussed. The as-deposited film contains approximately 20 at. % of boron which is chemical bound to W (W–B) having a resistivity of 128 μΩ cm. The film has an amorphous structure, which does not transform into crystalline phase during annealing. As a result of annealing in NH3 ambient, a tungsten ternary phase (W–B–N) forms at the surface; its binding configuration depends on the annealing temperature. Below 500 °C, nitrogen is chemically bonded to tungsten (W–N) while maintaining a W–B bond. Above 600 °C, nitrogen-rich W–B–N forms, in which nitrogen atoms have chemical binding with boron (B–N) and tungsten (W–N). It was found that a film annealed at higher temperatures has a resistivity of 107 μΩ cm, and thermal desorption of boron and nitrogen containing species is not observed during the thermal process. In addition, tungsten oxide formed at the surface d...