Tiny-Gap Titanium-Nitride-Composite MEMS Resonator Designs With High Power Handling Capability

Abstract

In this work, we have explored the power handling and motional resistance for the MEMS resonators fabricated using the Titanium-Nitride-Composite (TiN-C) platform on the <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$0.35~\mu \text{m}$ </tex-math></inline-formula> CMOS technology node. We have fabricated seven resonators at fundamental flexural mode (Design A) to study the effect of area increase on power handling and motional resistance. Furthermore, higher order mode designs – Design B (second order) and Design C (third order) in the same High Frequency (HF) range at the cost of area increase have been investigated. Use of multiple oxide fins help to improve the resonator performance without <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$Q$ </tex-math></inline-formula> degradation over fundamental mode and reduces residual stress effect, thus exhibiting a very flat device with a radius of curvature (R.O.C.) of 6.3, 17.2 and 12 cm for the fundamental 80 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu \text{m}$ </tex-math></inline-formula> wide pseudo free-free beam (PFFB), the second-order and third-order PFFB respectively. Additionally, we carried out Finite Element Method (FEM) simulation, equivalent circuit modeling, and experimental data verification for optimum MEMS design. We have used the 1-dB compression technique to extract the onset of the Duffing nonlinearity for the power handling capability of the fabricated resonators. In comparison to the <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$8~\mu \text{m}$ </tex-math></inline-formula> wide PFFB, the 80 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu \text{m}$ </tex-math></inline-formula> wide PFFB (Design A) is <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$9\times $ </tex-math></inline-formula> more efficient, and Designs B and C are <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$9.5\times $ </tex-math></inline-formula> and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$10\times $ </tex-math></inline-formula> more efficient in terms of power handling. [2022-0129]