High performance SAW devices with other element doped AlN films / layered structure substrates

2021 Fiscal Year Final Research Report

• Project/Area Number: 19K15024
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 21050:Electric and electronic materials-related
• Research Institution: University of Yamanashi
• Principal Investigator: Masashi Suzuki 山梨大学, 大学院総合研究部, 助教 (60763852)
• Project Period (FY): 2019-04-01 – 2022-03-31
• Keywords: 弾性表面波 / AlN薄膜 / 層構造基板

Outline of Final Research Achievements

In theoretical analysis for other metal element doped AlN film SAW devices, we demonstrated that polarity inverted ScAlN films/high-velocity layers/substrates for high order RSAW modes and c-axis parallel ScAlN films/quartz substrates for LLSAW modes had high phase velocities, high coupling factors and low acoustic attenuation.
In film growth for polarity inverted multilayered ScAlN films, we confirmed that Si doping to AlN films led to polarity inversion from Al-polarity to N-polarity. The polarity inverted SiAlN/AlN films could be fabricated. However, polarity inversion of ScAlN films by Si doping were not observed. We will try to control polarity direction of ScAlN films by further optimizing the concentration of Sc and Si doping in AlN films.

Free Research Field

弾性波デバイス

Academic Significance and Societal Importance of the Research Achievements

現在，弾性表面波（SAW）デバイスは移動通信機器の周波数フィルタとして実用化されている。今後さらなる通信の大容量化，高速化に向けて，より高周波帯域の次世代移動通信システムへの移行が検討されている。しかし，その高周波動作に対応できるSAWフィルタは現状の圧電単結晶基板単体のデバイス構造では実現困難とされている。そこで本課題では，「高SAW位相速度， 高結合係数，低SAW伝搬減衰」のすべてを満たし，かつ形成も容易な 高結合係数を実現する他元素ドープAlN圧電層/伝搬減衰を抑制する高音速層/高音速基板からなる多層構造基板の創成とその基板を用いたSAWデバイスの開発を行った。