Polarization inverted ScAlN multilayers for high power SMR

2023 Fiscal Year Final Research Report

• Project/Area Number: 21K18734
• Research Category: Grant-in-Aid for Challenging Research (Exploratory)
• Allocation Type: Multi-year Fund
• Review Section: Medium-sized Section 21:Electrical and electronic engineering and related fields
• Research Institution: Waseda University
• Principal Investigator: Yanagitani Takahiko 早稲田大学, 理工学術院, 教授 (10450652)
• Project Period (FY): 2021-07-09 – 2024-03-31
• Keywords: 分極反転構造 / BAWフィルタ / SMR / ScAlN

Outline of Final Research Achievements

Bulk acoustic waves (BAW) filters are used for RF filters in smartphones, and their power durability is approximately 1 W. On the other hand, a large-size dielectric resonators are mainly used for RF filters in cellular phone base stations whose power durability require tens of watts. In recent years, however, increase the number of base stations for higher frequencies needs more compact base stations. Therefore, in this study, we propose a high power durability BAW filters for the future use in base stations. Since heat is the main degradation factor of BAW filters, increasing the volume of the piezoelectric thin film improves the power durability of BAW filter. We here report the polarization inverted ScAlN multilayers thin film and a single layer ScAlN thin film on an acoustic Bragg reflector and compared their power durability.

Free Research Field

圧電薄膜共振子

Academic Significance and Societal Importance of the Research Achievements

現在スマートフォンのRFフィルタには、バルク弾性波（Bulk Acoustic Wave）を用いたBAWフィルタが用いられており、その耐電力性は1 W程度である。一方、携帯電話基地局のRFフィルタには主に大型の誘電体共振器が用いられており、その耐電力性は数十W必要とされている。しかし近年、高周波化に伴う基地局増設の必要性から、基地局の小型化が求められている。そこで本研究では、将来的にBAWフィルタを基地局のRFフィルタとして利用することを目的とした、BAWフィルタの耐電力性向上に関する提案した。