Research And Application Of Single Crystal Diamond Micro/nano Electromechanical System(MEMS/NEMS)

Diamond has been applied in the field of MEMS/NEMS due to its unique properties.Compared with polycrystalline/nanocrystalline diamond,single crystal diamond(SCD)is particularly worth exploring because of its better performance.On the other hand,single crystal diamond has little inherent energy loss,and can be coupled with its naturally rich embedded high-quality NV color center through mechanical resonator.It is an excellent material for the preparation of highly potential hybrid quantum devices.In this thesis,we introduce the sample preparation,testing,and more application research based on the single crystal diamond cantilever beam.In terms of improving device performance,we have reduced the energy loss on the surface of the NEMS cantilever through high-temperature oxygen annealing and get the Q factor improved.In order to completely remove the effects of defects caused by the preparation process,we used long-term oxygen annealing,and got a pleasant result,with the Q value of the resonator reaching one million level.In the exploration of diamond applications,we took advantage of the fact that the frequency of the cantilever is very sensitive to the change of the mass of the resonator.We were interested in the etching of diamond in hydrogen plasma,and carefully studied this process,and successfully achieved the accurate characterization of etching rate.In addition,considering the operation of the optical readout method that we have been using before together with the necessary optical instruments,which is a big obstacle for the integration of diamond MEMS.In order to realize the integration,we must use other methods to obtain the signal of the diamond resonator.Undoubtedly,the realization of electrical reading has become our preferred choice.Using its piezoresistive effect,the diamond vibrator is successfully read out electrically.We have successfully applied electrical readout to the diamond cantilever by coating an ultra-thin metal(Au)electrode on the surface of the cantilever based on the piezoresistive effect.First of all,we introduce some basic concepts of sample preparation and testing,and introduces related theoretical knowledge.The resonator samples involved in this thesis are all prepared by the IAL method.Since the ion implantation process of this method has an impact on the performance of diamond,which seriously limits the quality factor of the resonator,we expect to reduce the effect by high-temperature oxygen annealing.We analyze the effect of annealing in a high-temperature oxygen environment on the performance of diamond NEMS cantilever resonators.When the annealing temperature is selected to be relatively low,the Q factor and resonance frequency of the vibrator do not change significantly,and when the temperature rises to 500?,the quality factor of the vibrator is significantly improved.Annealing can reduce the surface defects induced by IAL preparation technology,reduce the corresponding energy loss and improve the Q factor of single crystal diamond resonator.In next step,we remove the diamond defect layer affected by ion implantation through long-term high-temperature oxygen annealing to improve the Q factor and performance of the SCD MEMS.Atomic layer etching(ALE)technology combined with controllable high-quality diamond growth technology can remove the energy loss caused by the defect layer in the diamond mechanical resonator.Therefore,an all-diamond MEMS resonator with an ultra-high Q factor(million level)is realized.This work has created the conditions for the development of next-generation high-performance,ultra-sensitive integrated MEMS/NEMS and optomechanical systems,sensing,scanning microprobes,and hybrid quantum devices.We try to discover more potential applications of SCD oscillators.We utilize the shift of single crystal diamond(SCD)cantilever's resonance frequency to characterize the corrosion rate of SCD with(100)oriented surface in hydrogen plasma at the temperatures of 800-900?.The etching rate measurement method based on MEMS/NEMS can be extended to the field of etching research of other materials in reactive gases or mixtures(not limited to hydrogen plasma),especially for materials with extremely low etching rates.Finally,we show the electrical readout method of single crystal diamond cantilever resonator.Based on the piezoresistive effect of the metal coating above the cantilever,the mechanical resonance signal of the diamond cantilever beam was successfully converted,thus getting rid of the limitation of the laser system in the optical readout method.The electrical readout of diamond MEMS/NEMS devices provides convenience for the next integration of diamond MEMS/NEMS devices with other electronic components.