Effect Of Temperature On The Micro-wear Of Monocrystalline Silicon In Water

Monocrystalline silicon has been widely used as a structural function material for mi-cro/nano devices because of its excellent physical and chemical properties.However,there are many micro-wear issues in both chemical mechanical polishing(CMP)processing and the use of silicon-based micro/nano devices in water.Temperature is a key factor affecting the mi-cro-wear of materials(especially tribochemical wear),but the research about it is still lacking so far.For example,the processing rate and surface quality in CMP of monocrystalline silicon are related to temperature closely,however,the relative mechanism has not been well studied.In addition,the operation of micro/nano devices in liquid environment is very sensitive to the change of ambient temperature,while the wear problem caused by temperature has not been comprehensively studied.In order to clear the effect of ambient temperature on the wear fail-ure of micro/nano devices in liquid,and to reveal the effect of temperature on the atomic re-moval of material in CMP of monocrystalline silicon,it is necessary to study the micro-wear of monocrystalline silicon in water at various temperatures.In view of the above,the effect of liquid temperature on the micro-wear of monocrystal-line silicon was studied in this paper by using multi-probe micro/nano fabrication apparatus and atomic force microscopy(AFM),respectively.In order to reveal the mechanism of liquid temperature on the micro-wear of monocrystalline silicon,surface properties of monocrystal-line silicon after bathing in water at various temperatures were characterized by AFM and EDX.Furthermore,Raman spectroscopy was used to investigate the dependence of Si-H and Si-OH groups on wear of monocrystalline silicon in water at various temperatures.The main experimental results and conclusions are summarized as below.(1)The variation of micro-wear of monocrystalline silicon in water at different tempera-tures was revealed.The wear of silicon/SiO2 pair under micrometer contact in water included mechanical wear and tribochemical wear,and tribochemical wear plays a dominant role.Under the mi-crometer contact,the wear volume of mono crystalline silicon in water increased with the in-crease of temperature.Here,the mechanical wear part was not sensitive to temperature change,while the increase of water temperature promoted the tribochemical wear of silicon/Si02 pair obviously.(2)The variation of tribochemical wear of monocrystalline silicon in water at different temperatures was revealed.Under the nanometer contact,the wear of silicon/SiO2 pair in water was only dominated by tribochemical wear.With the increase of water temperature,the original silicon surface un-derwent a process from no significant damage to wear generation.Under the same conditions,wear marks appeared on the hydrophobic silicon surfaces.With the increase of temperature,the wear depth and volume increased slightly,then reached peak value at room temperature of 25?,after that the value reduced quickly.(3)The effect of temperature on micro/nano wear of mono crystalline silicon in water was elucidated.The wear rate and temperature of micrometer contact wear of monocrystalline silicon in water can be well fitted by the Arrhenius' equation,and the Raman spectroscopy test showed that the comprehensive intensity of Si-H and Si-OH groups in debris increased with the in-crease of water temperature.Therefore,the promotion of temperature on micrometer contact wear of monocrystalline silicon in water is due to the promotion of temperature on the hydrol-ysis reaction.Further analysis showed that the nanoscale tribochemical wear of monocrystal-line silicon at different water temperatures might be closely related to water contact angle or hydrophobicity of silicon surfaces.With the increase of water temperature,the hydrophobicity of original silicon surface increased and the thickness of water film between silicon/Si02 pair reduced.As a result,the formation of "Si-O-Si" bonding bridge between the contact surfaces became more easily,and the tribochemical wear of original silicon became more serious.Dif-ferent with original silicon,the hydrophobicity of hydrophobic silicon decreased with the in-crease of water temperature,and the water film became thicker.Thus,the formation of"Si-O-Si" bonding bridges between the contact surfaces would be more difficult,and the tri-bochemical wear became weeker.