High frequency NEMS resonator based on TiN for Mass/Bio sensors

Abstract

Recently, as the technology of fabrication for nano-sized structure is developed, NEMS(Nano-Electro-Mechanical System) are attracting attention due to their small size. Nanomechanical resonators or NEMS present interesting possibilities in a number of application as well as fundamental research. Due to high resonant frequency(~MHz), very small mass, low intrinsic dissipation which is limited at microscale dimensions, demonstrations and applications of unprecedented sensitivity available from nanomechanical devices such as sub-single-charge electrometry, single-electron-spin paramagnetic resonance, zeptogram scale mass sensors, and sub-femto-metre displacement sensing. In this thesis, MHz range nanomechanical resonator is demonstrated and developed based upon novel material titanium nitride which superior properties than other materials such as SiC, AlN, Si, GaAs. Proposed titanium nitride material has many advantages for nano-mechanical resonator in view of fabrication, design, performance, SNR. Using conventional CMOS-compatible fabrication, we made a stiff doubly clamped beam composed of only poly-crystalline titanium nitride without additional metal layer and temperature of fabrication is $300\degC$ which is very low thermal budget to fertile the reliable imbedded CMOS-circuit. At the same time, processing for making suspended structure is very simple and reliable. Due to constructing beam with single material, devices achieve a high quality factor without no interfacial friction and loss. In addition, titanium nitride have a high elastic modulus of 400~600GPa, which results high resonant frequency and sensitivity. Fundamental characterization of doubly clamped beam based upon titanium nitride were measured and compared with other research group. Maximum resonant frequency is obtained to about 135MHz with 2600 of quality factor which performance reach the $4 \times 10^{11}$ value. This performance is comparable or superior to other research group which sho...