Characteristics of threshold-voltage shifts for nano p-TFT under alternating mechanical stress

Accurate measurement of nano-electromechanical system (NEMS) resonator is difficult due to parasitic effect, piezoresistive effect and etc. In order to get higher measurement precision, detailed studies are needed to learn and understand its behavior under alternating mechanical stress during NEMS resonance. Devices with nano TFT channel have been fabricated and tested to study the effects of the alternating mechanical stress on the resonators. The TFT channel is nano scale in vertical direction normal to the device plane. After applying alternating mechanical stress, output curve shift is observed. It is found that the drift is enlarged with the increase of vibrating frequency and decrease of vibrating amplitude. It is assumed from experimental results that internal friction is the major factor of generating trapped electron and charge in the silicon-insulator interface. The phenomenon can be used to further understand the behavior and calibrate the measurement of NEMS resonators later.