Low temperature (210 °C) fabrication of Ge MOS capacitor and controllability of its flatband voltage

Hajime Kuwazuru, Taisei Aso, Dong Wang, Keisuke Yamamoto

Research output: Contribution to journalArticlepeer-review

1 Citation (Scopus)

Abstract

Germanium (Ge) and germanium tin (GeSn) are strong candidate materials for novel electronic device such as spin MOS field-effect transistor (FET) or flexible devices. A high-quality insulating layer on Ge(Sn) should be formed at low temperatures to realize these applications. In this study, we fabricated a Ge MOS capacitor (CAP) and n-MOSFET with a SiO2/GeO2 gate dielectric using an electron cyclotron resonance plasma process and subsequent post-deposition annealing at a low temperature of 210 °C. The MOSCAPs show the typical electrical characteristics without significant degradation compared with the samples fabricated at a higher temperature of 450 °C. The n-MOSFET shows distinct output characteristics with clear saturation behavior and high current drivability. From the flatband voltage comparison among different annealing temperatures, high-temperature annealing induces the interface dipole formation in the gate insulator, significantly shifting flatband voltage to a negative direction. X-ray photoelectron spectroscopy analysis suggests that the origin of the interface dipole is oxygen atom movement at a SiO2/GeO2 interface. This information will be an important guideline for fabricating a high-quality insulator on Ge(Sn) at low temperatures.

Original languageEnglish
Article number108427
JournalMaterials Science in Semiconductor Processing
Volume178
DOIs
Publication statusPublished - Aug 1 2024

All Science Journal Classification (ASJC) codes

  • General Materials Science
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering

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