AVS 51st International Symposium
    Applied Surface Science Thursday Sessions
       Session AS-ThM

Paper AS-ThM5
Applications of ARXPS to Semiconductor Fabrication and Characterization

Thursday, November 18, 2004, 9:40 am, Room 210A

Session: High-k Dielectrics
Presenter: P. Mack, Thermo Electron Corporation, UK
Authors: P. Mack, Thermo Electron Corporation, UK
M. Shakespeare, Thermo Electron Corporation, UK
A. Wright, Thermo Electron Corporation, UK
R.G. White, Thermo Electron Corporation, UK
Correspondent: Click to Email
In modern semiconductor fabrication, two trends are clear. Layers are becoming thinner and the materials are becoming chemically more complex. For these reasons, XPS is becoming increasingly important as a characterisation tool. It is well known that XPS provides chemical state information from the near surface region and commercial tools exist to handle wafers of up to 300 mm. Now that the thickness many of the layers used in semiconductor technology are less than the escape depth of the photoelectrons, the technique can be used to characterise the layers and their interface with the substrate. If angular resolution is combined with the XPS technique (angle resolved XPS or ARXPS) it becomes possible to measure the thickness of layers, and the distribution of the materials and chemical states within the layer non-destructively. For example, not only can ARXPS measure the thickness of an oxynitride layer but it can also determine the way in which nitrogen is distributed through the layer. The nitrogen distribution affects both the electrical properties and the accuracy of dose measurements. In the case of high-k dielectrics, the nature and thickness of both the high-k layer and any intermediate silicon dioxide or silicate layer can be determined. The combined electrical properties of these layers determine the integrity of the dielectric stack. By using the technique of parallel ARXPS it becomes possible to make all of these measurements from intact 300 mm wafers. ARXPS can produce depth profiles without the need for sputtering. This means that ARXPS has the potential to be applied to shallow implants, such as arsenic in silicon. This has the advantage over SIMS profiles that it does not suffer from near-surface sensitivity artefacts. Examples of materials characterisation from a range of semiconductor thin films will be shown.