Font Size: a A A

Study On Interface And Performance Of Hafnium Based Gate Dielectric Layer Polymer Transistors Prepared By Solution Method

Posted on:2024-08-25Degree:MasterType:Thesis
Country:ChinaCandidate:G ChenFull Text:PDF
GTID:2568307136993509Subject:New Generation Electronic Information Technology (Professional Degree)
Abstract/Summary:PDF Full Text Request
Polymer Thin Film Transistor(PTFT)has potential advantages such as flexibility,low-temperature processing,low-cost preparation,and high-throughput manufacturing,and is widely used in fields such as flexible displays and sensors.However,reducing the operating voltage of polymer thin film transistors in applications such as low-voltage sensors remains a challenge.To address this issue,researchers have proposed using materials with high dielectric constants or reducing the thickness of the gate dielectric layer to reduce the operating voltage.Among them,high dielectric constant hafnium based thin films are a commonly used material.However,high dielectric constant materials can bring interface state problems in practical applications,which affect device performance.In response to this issue,this article investigates the performance of high dielectric constant hafnium based thin films as gate dielectric layer polymer thin film transistors.Based on this,further interface optimization is carried out to achieve low voltage operation and solve interface state problems.The specific research content includes the following aspects:Preparation and characterization of hafnium based gate dielectric thin films.Using deionized water as the solvent for the precursor solution of hafnium oxide(Hf O2),the film formation smoothness is improved by accelerating the spin coating rate and using multiple spin coating methods.When using anhydrous ethanol as a solvent for zirconia(Zr O2)precursor solution,the water molecular content in the spin coating atmosphere is a key factor affecting film formation.In a relatively dry environment,a film with a root mean square roughness RMS of less than 1nm can be obtained.Comparing the film formation of solution method hafnium zirconium oxide(Hf0.5Zr0.5O)films under different annealing temperatures,it was found that the film annealed at 450℃had the smallest grain size.Performance of different hafnium based gate dielectric layers prepared by solution method in polymer thin film transistor devices.The experiment shows that using Hf O2 as the gate dielectric layer can obtain a threshold voltage of-1.82V,a saturation mobility of 0.182cm2V-1s-1,and a switching ratio of 5.8×103 devices.Devices with Hf O2/Zr O2,Zr O2/Hf O2,and HZO composite oxides as gate dielectric layers were prepared by overlapping spin coating and mixed solution methods.The results show that the threshold voltage of the device using overlapping spin coating method to prepare composite oxides as gate dielectric layers is reduced to-1.13V;For devices using mixed solution method to prepare composite oxides as gate dielectric layers,the saturation mobility is effectively increased to 0.204cm2V-1s-1,and the switching ratio is increased to 5.2×104,increased by an order of magnitude.From the saturation characteristic curve,there is almost no hysteresis phenomenon in devices using composite oxides as gate dielectric layers prepared from mixed solutions.Passivation of high dielectric constant(high-k)interfaces in polymer thin film transistor devices.Three different polymer materials,methyl methacrylate(PMMA),polystyrene(PS),and polyvinyl alcohol(PVA),were selected as passivation layers and inserted into the hafnium zirconium oxide(HZO)gate dielectric layer polymer thin film transistor device to study their impact on device performance.Through comparative experiments,it was found that after inserting the passivation layer of polymer polymer materials,the device performance was significantly improved,the threshold voltage decreased to-1.16V,and the current switching ratio increased to 6.4×105,the lowest subthreshold swing is reduced to 0.617V/dec,and the saturation mobility of the PMMA passivation layer device is increased by 85%.Due to the different molecular structures of the three polymer materials,there are great differences in the sweep test transfer characteristic curve.PVA has hysteresis,while PMMA has a small hysteresis,and PS has almost no hysteresis.Finally,optical microscopy observation revealed that after inserting the PMMA passivation layer,the polymer semiconductor DPPT-TT thin film deposited by spin coating arranged more tightly and exhibited a certain degree of orderliness,which explains the significant increase in device saturation mobility after inserting the PMMA passivation layer.
Keywords/Search Tags:Polymer thin film transistor, hafnium based gate dielectric layer, passivation layer, DPPT-TT, liquid phase process
PDF Full Text Request
Related items