Research On Performance Of Displacement Sensor Based On MOS Structure

Displacement sensors involve a series of interdisciplinary subjects such as semiconductor,computer and mechanical engineering.They play an increasingly important role in the field of information technology and have a wide range of applications in the field of measurement and automation.Different from the traditional displacement sensor,the semiconductor displacement sensor has the advantages of high sensitivity,which is gradually attracting the attention of some experts and scholars,and is in the metal?metal oxide?-oxide-semiconductor(MOS:Metal?Metal oxide?A new type of photoelectric effect has been found in the structure of-Oxide-Semiconductor,and this new photoelectric effect can be used to produce highly sensitive displacement sensors.Its principle is that when the laser irradiation point scans the surface of the sample of the MOS structure,the sample will have an electrical signal response,and the electrical signal has regularity.We call this phenomenon the lateral photovoltaic effect.Based on this photoelectric effect,samples can be fabricated into sensors that detect small displacements and have higher precision than conventional sensors.In addition,the MOS structure also has a bipolar resistance effect.Since the bipolar resistance not only has a linear relationship with the position of the illumination point of the light source,but also has a bipolar characteristic,the bipolar resistance effect can be applied to the photodiode and the photo-controlled varistor.At present,the nano-film is coated on the silicon substrate by magnetron sputtering,high vacuum resistance evaporation coating,sol-gel method,etc.,and then the required experimental data is obtained by the three-dimensional optical moving platform.The sample is fixed on the three-displacement optical moving platform by the clamping device.When the sample moves in a certain step and trajectory in the X-axis,Y-axis and Z-axis directions,the sample is electrically moved as the point source moves on the surface of the sample.Then import the data into the Origin software to draw the graph.In this paper,nano-sized films are grown on silicon substrates by high vacuum resistance evaporation coating,magnetron sputtering and sol-gel methods.Then,the samples are fixed in three-displacement optics using the clamping device designed by our laboratory.Then,the laser is turned on,and the laser is irradiated onto the sample of the MOS structure through the convex lens and the light source aperture,and then the step size of the optical moving platform is controlled by the computer,and the transient electrical signal response generated when the light source moves on the sample surface is recorded.The obtained experimental data was imported into Origin to obtain the characteristic curve,and then the curves were studied and analyzed.In this paper,AZO-SiO₂-Si and Ni-SiO₂-Si based on MOS structure are studied,and their lateral photovoltaic effect and bipolar resistance effect are studied.Because the production principle of the displacement sensor is mainly the lateral photovoltaic effect,the focus of this paper is on the lateral photovoltaic effect of the MOS structure.We have tried MOS structural samples made of new materials such as Al,Cu,AZO,ITO and Graphene.Lateral photovoltaic effects can also be enhanced by improving the fabrication process of the MOS structure and improving test conditions,such as changing the thickness of the coating layer or increasing lateral illumination.Based on this,the practical application of MOS structure as various optoelectronic devices is analyzed.The sensitivity of AZO-SiO₂-Si is 125.7 m V/mm,and the sensitivity of Ni-SiO₂-Si is 103.6 m V/mm,both of which meet the requirements for developing high-precision sensors.This paper briefly introduces the theory of MOS displacement sensor,the process of MOS structure fabrication and the measurement method of its characterization.Later,we also introduced the lateral photovoltaic effect of the laser irradiation point scanning in different directions,and studied the electron interference effect of the porous nano film coated on the surface of the MOS structure,so as to make the sensitivity of AZO-SiO₂-Si.Increased from 125.7m V/mm to 202.9 m V/mm.Finally,the Bipolar Resistance Effect and lateral photovoltaic effect of the new Si-Si_0.7Ge_0.3-Si and Ge/Ni structures are studied.It is found that it can also be used as a displacement sensor to measure small displacements,which provides a new direction for the research of displacement sensors.