Amorphous Dielectric Thin Films with Extremely Low Mechanical Loss

Archives of Metallurgy and Materials

J.E. Karel¹  F. Hellman¹  T.H. Metcalf²  X. Liu²  D.R. Queen³ 

[1] DEPARTMENT OF MATERIALS SCIENCE AND ENGINEERING, UNIVERSITY OF CALIFORNIA, BERKELEY, BERKELEY, CALIFORNIA 94720, USA;NAVAL RESEARCH LABORATORY, CODE 7130, WASHINGTON, DC 20375, USA;NRC POSTDOCTORAL ASSOCIATE, CODE 7130, WASHINGTON, DC 20375, USA

关键词: Keywords: Internal friction;    amorphous silicon;    elastic modulus;    speed of sound;    tunneling systems;   

DOI  :  10.1515/amm-2015-0059

学科分类：金属与冶金

来源: Akademia Gorniczo-Hutnicza im. Stanislawa Staszica / University of Mining and Metallurgy

【 摘 要 】

The ubiquitous low-energy excitations are one of the universal phenomena of amorphous solids. These excitations dominate the acoustic, dielectric, and thermal properties of structurally disordered solids. One exception has been a type of hydrogenated amorphous silicon (a-Si:H) with 1 at.% H. Using low temperature elastic and thermal measurements of electron-beam evap-orated amorphous silicon (a-Si), we show that TLS can be eliminated in this system as the films become denser and more structurally ordered under certain deposition conditions. Our results demonstrate that TLS are not intrinsic to the glassy state but instead reside in low density regions of the amorphous network. This work obviates the role hydrogen was previously thought to play in removing TLS in a-Si:H and favors an ideal four-fold covalently bonded amorphous structure as the cause for the disappearance of TLS. Our result supports the notion that a-Si can be made a “perfect glass” with “crystal-like” properties, thus offering an encouraging opportunity to use it as a simple crystal dielectric alternative in applications, such as in modern quantum devices where TLS are the source of dissipation, decoherence and 1/f noise.

【 授权许可】

Unknown