| AVS 61st International Symposium & Exhibition | |
| Novel Trends in Synchrotron and FEL-Based Analysis Focus Topic | Monday Sessions |
| Session SA-MoM |
| Session: | Synchrotron Studies of Processes in Energy Conversion, Electronic Devices and Other Materials I |
| Presenter: | Greg Hughes, Dublin City University, Ireland |
| Authors: | G. Hughes, Dublin City University, Ireland L. Walsh, Dublin City University, Ireland J.C. Woicik, National Institute of Standards and Technology (NIST) P.K. Hurley, Tyndall National Institute, Ireland |
| Correspondent: | Click to Email |
Hard x-ray photoelectron spectroscopy (HAXPES) is emerging as a technique which has the capability to provide chemical and electronic information on much larger depth scales than conventional XPS. This has potential applications in the study of oxide/semiconductor and metal/semiconductor buried interfaces found in device structures, particularly after annealing cycles. In this presentation results of combined hard x-ray photoelectron spectroscopy (HAXPES) and electrical characterisation measurements on identical Si and III-V based metal-oxide-semiconductor (MOS) structures will be presented. The experimental findings obtained indicate that surface potential changes at the semiconductor/dielectricinterface due to the presence of a thin metal gate layer can be detected with HAXPES. Changes in the semiconductor band bending at zero gate voltage and the flat band voltage for the case of metal gate layers derived from the semiconductor core level shifts observed in the HAXPES spectra are in agreement with values derived from C-V measurements.
The III-V material InGaAs, shows promise as the channel material in high speed n-MOSFETs however, the issue of low resistance source/drain (S/D) contacts to InGaAs remains. A possible solution is to find a self-aligned silicide like material (salicide) to act as the S/D contacts. The search for this material has recently focussed on Ni-InGaAs, due to its promisingly low Rs and its apparent abrupt interface with InGaAs. Results of a HAXPES study of the Ni-InGaAs alloy system has been undertaken in order to determine the nature of the Ni-InGaAs interface and its evolution as a function of annealing temperature. The results show that Ni readily interacts with InGaAs upon deposition at room temperature resulting in significant inter-diffusion and the formation of NiIn, NiGa, and NiAs alloys. This information when combined with x-ray absorption spectroscopy (XAS) measurements can be used to develop a structural and chemical compositional model of the Ni-InGaAs system as it evolves over a thermal annealing range of 250-500 °C.