Design And Fabrication Of A Micro-chip For In-situ TEM Characterization

Benefiting from the small dimensions and extraordinary properties,functional nanomaterials have been attracting great interest in the development of next-generation electronic devices.Since the properties of nanomaterials are closely related to their shapes,structures,and qualities,it is of great importance to controllably fabricate high-quality nanomaterials in demand for specific device applications.However,current fabrication strategies are most in a blind mode,i.e.,the reaction and growth processes are invisible,and this brings difficulty in modulation and optimization of the nanomaterials during their growth stage.Upon this issue,this thesis designs and fabricates a type of micro-chip that can be used in TEM to provide a high-pressure environment for characterization of nanomaterial growth.The main work and results of this thesis are as listed below.1.A type of micro-chip with two sealed heating zones is designed for in-situ TEM observation of the vapor-phase growth of nanomaterials.The chip consists of two parts,including a cover chip and a bottom chip,with a metal coil as the heating structure and silicon nitride films as the window of the micro-cavity.The force-thermal distribution of the chip is simulated using a software,and the results show that the heating temperatures of the two heating zones can be independently controlled.2.Using microfabrication techniques,the fabrication flow of the chip is designed and fabricated.The chip was also characterized by SEM and the inconsistency of different chips was small and acceptable.3.The hermeticity,imaging quality and heating effect of the chip were tested in this thesis.The results show that the chip has good hermeticity and a little impact on the imaging quality,and the chip structure is still intact under temperature above 300℃.Based on this chip,the sublimation process of tellurium nanowires was characterized ex-situ.The results show that the tellurium nanowires sublimate rapidly under a voltage load of 1.4 V.The micro-chip in this paper provides a new technique for in-situ observation of the vapor phase growth with the advantages of low cost and flexible use,which expands the application scope of in-situ TEM.