High Mobility Hydrogen Doped Indium Oxide Prepared By Atomic Layer Deposition And Research Of Photoelectric Properties

With the development of Aeronautics and astronautics technology,the demand for the integration of optical and electrical devices has also put forward higher requirements.How to achieve the unity of infrared imaging（high transmittance in mid infrared）and electromagnetic shielding（high conductivity）of weapons and equipment has become a key problem limiting the current development.Transparent conductive materials are the best choice to solve the above problems because they have both transmission and conductivity.According to the cooperative regulation mechanism of infrared transparent conduction,by increasing the carrier mobility and reducing the carrier concentration,the unity of infrared high transmittance and high conductivity can be achieved.At present,the industrialization of metal mesh and tin doped indium oxide（ITO）film can not meet the high transmittance requirements of infrared band.Therefore,how to achieve high carrier mobility has become a hot topic.In order to solve the above problems,In₂O₃:H film is selected,which is a special transparent conductive oxide film.On the one hand,hydrogen has a very small volume and mass,and will not produce impurity scattering in the process of electron transport;On the other hand,hydrogen is distributed in the gap of the indium oxide lattice,resulting in almost no lattice distortion,so it does not increase the number of grain boundaries and reduce the grain boundary scattering.The combined effect of these two factors makes the hydrogen doped indium oxide（In₂O₃:H）thin films have high carrier mobility,which can achieve high infrared transmittance by reducing the carrier concentration on the basis of ensuring the electrical properties.In this paper,the growth rate,micro structure and photoelectric properties of In₂O₃:H films were investigated by changing the deposition process parameters.When the deposition temperature is 100℃,incomplete reaction occurs during deposition,and the growth rate is slow.The film is amorphous.At this time,the carrier mobility is low,which is only 30.18 cm2/（V·s）,and the optical properties are good,the transmittance can reach 80%at 4 μm;With the increase of deposition temperature,the growth rate gradually stabilized at 0.1nm/cycle,the amorphous state gradually changed to crystalline state,the carrier mobility increased sharply,and the highest was 64.05cm2/（V·s）,and the carrier concentration and the optical properties decreased.The ratio of deposition time of InCp/（O2+H2O）and the reaction time of InCp have little effect on the electrical and optical properties.With the increase of deposition period,the carrier mobility can reach up to 80 cm2/（V·s）,but the optical performance is very poor,the transmission rate at 4 μm is only 39.5%.In addition to the deposition process parameters,the effects of post annealing process on the microstructure and photoelectric properties of In₂O₃:H films were also investigated.In₂O₃:H thin films deposited at 150℃ for 600 cycles were annealed at different annealing temperatures and times.The results show that the carrier mobility increases sharply after annealing,up to 90 cm2/（V·s）,the carrier concentration decreases sharply,and the optical properties are also improved,the transmittance can reach 70%at 4 μm.The results show that the carrier concentration decreases to 1019 cm-3,the transmittance can reach 83%at 4 μm.The uniformity of the coating on the flat and hemispherical surfaces was also investigated.By placing Si wafers in different positions of the cavity to characterize the deposition thickness and calculate the non-uniformity,the cleaning time was extended from 10s to 20s,resulting in the non-uniformity reduced from 38.8%to 3.4%.Fluent software is used to simulate the flow field distribution of the top hole and the side hole.The results show that the air pressure and flow velocity at the inlet are relatively large,which may cause great non-uniformity.The subsequent optimization design of the model is also needed.Finally,the relationship between shielding effectiveness and surface resistance is simulated by CST software,and the results show that the surface resistance is reduced to 20 Ω/sq when the electromagnetic shielding effectiveness is up to 20dB.