Sc_xAl_(1-x)N壓電共振器實現5G毫米波行動通訊積體化

Sc_xAl_(1-x)N Piezoelectric Resonator Promising the Applications for 5G Millimeter Wave Communication System

洪茂峰(Mau-Phon Houng) ； 洪肇蔚(Jau-Wei Hung)

《科儀新知》 233期 (2022/12) Pp. 60-69

摘要

行動通訊為現代人的生活帶來許多便利，而通訊系統中濾波電路決定了通訊品質的良窳。AlN濾波器因具有可高頻操作、對溫度穩定性高及與CMOS製程相匹配等優點，可實現濾波晶片積體化，滿足行動通訊短小輕薄的要求，故為目前製作濾波晶片的主力。但現今行動通訊進展到5G境界，要求濾波器能操作於更高的頻率，更大的頻寬，具有信號損漏更低的Q值，對此，AlN濾波器漸露窘態，但有學者發現在AlN中摻入Sc原子，其造成的應力將使Sc_xAl_(1-x)N產生較AlN更好的壓電表現。此一新材料的興起，當然帶來很多研發的挑戰。本文將對ScAlN的壓電特性與材料品質的相依性、各式ScAlN元件（BAW、FBAR、LWR、SMR）的製程與電特性、優化其電特性的方法以及應用於集能元件與高頻通訊系統之潛力等議題作詳細的介紹。

並列摘要

The 5G wireless standards is a promising solution for the increasing number of bands and the complexity in the wireless communication system. Due to CMOS compatibility and well-developed techniques, AlN has been popular in the wireless communication system. However, limited piezoelectric coefficients, k_t^2, was observed in AlN films which affecting the bandwidth of the filter. Recent work shows an increase in k_t^2 values up to 4-5 times larger than AlN can be obtained by doping Sc into AlN, that means, Sc_xAl_(1-x)N-base filters can be played as a potential device in the 5G era. For such a new material, some kinds of important challenges, such as, material growth Prameters, devices fabrication techniques, improve methods on device characteristics and the roles of Sc_xAl_(1-x)N-base resonator applied on millimeter wave communication system and energy harvesting devices will be discussed.