Optimization of LPCVD phosphorous-doped SiGe thin films for CMOS-compatible thermoelectric applications

Research output: Contribution to journalResearch articleContributedpeer-review

Contributors

  • Caroline Schwinge - , Fraunhofer Institute for Photonic Microsystems (Author)
  • Kati Kühnel - , Fraunhofer Institute for Photonic Microsystems (Author)
  • Jennifer Emara - , Fraunhofer Institute for Photonic Microsystems (Author)
  • Lisa Roy - , Fraunhofer Institute for Photonic Microsystems (Author)
  • Kati Biedermann - , Fraunhofer Institute for Photonic Microsystems (Author)
  • Wenke Weinreich - , Fraunhofer Institute for Photonic Microsystems (Author)
  • Sabine Kolodinski - , Global Foundries Dresden (Author)
  • Maciej Wiatr - , Global Foundries Dresden (Author)
  • Gerald Gerlach - , Chair of Solid State Electronics, TUD Dresden University of Technology (Author)
  • Maik Wagner-Reetz - , Fraunhofer Institute for Photonic Microsystems (Author)

Abstract

The incessant downscaling of building blocks for memory and logic in computer chips requires energy-efficient devices. Thermoelectric-based temperature sensing, cooling as well as energy harvesting could be useful methods to reach reliable device performance with stable operating temperatures. For these applications, complementary metal-oxide-semiconductor (CMOS)-compatible and application ready thin films are needed and have to be optimized. In this work, we investigate the power factor of different phosphorous-doped silicon germanium (SiGe) films fabricated in a 300 mm CMOS-compatible cleanroom. For the thermoelectric characterization, we used a custom-built setup to determine the Seebeck coefficient and sheet resistance. For sample preparation, we used low pressure chemical vapor deposition with in situ doping and subsequent rapid thermal annealing on 300 mm wafers. Thin film properties, such as film thickness (12-250 nm), elemental composition, crystallinity, and microstructure, are studied via spectroscopic ellipsometry, x-ray photoelectron spectroscopy, x-ray diffraction, atomic force microscopy, and TEM. The SiGe-based thin films vary in the ratio of Si to Ge to P and doping concentrations. A power factor of 0.52 mW/m K2 could be reached by doping variation. Our results show that SiGe is a very attractive CMOS-compatible material on the 300 mm wafer level and is immediately ready for production of thermoelectric embedded applications.

Details

Original languageEnglish
Article number031903
JournalApplied physics letters
Volume120
Issue number3
Publication statusPublished - 17 Jan 2022
Peer-reviewedYes

External IDs

ORCID /0000-0002-7062-9598/work/174430584

Keywords

ASJC Scopus subject areas