Research On The Characteristics Of GaN HEMT Based On HfZrO Ferroelectric Thin Film Gate Dielectric

The third generation semiconducting gallium nitride(Ga N)is regarded as a strong competitor of silicon(SI)materials due to its wide band gap,high electron mobility,high saturation speed and high breakdown field strength.Due to the spontaneous polarization and piezoelectric polarization effect of the Al Ga N/Ga N High electron mobility transistor(HEMT),large densities of 2DEG exist at the interface of Al Ga N/Ga N heterojunction.Ga N HEMTs have excellent high frequency and power characteristics,so they are hotspot of the current Ga N transistor research.Ferroelectric materials which have polarization characteristics,with different electric field direction will produce different polarization direction and polarization intensity.When the applied electric field is removed,a certain amount of polarized electric field can still be maintained in a certain direction.There is a certain amount of electric field can change the polarization direction of ferroelectric materials.The inherent property of polarization makes the design of semiconductor devices have a new dimension,which can control and maintain the electric field of specific structure position of the device through polarization.In this paper,ferroelectric materials are introduced into Ga N based HEMT devices,to study the interaction between ferroelectric hafnium zirconium oxide(HfZrO)thin film materials and Ga N HEMT devices,so as to solve the key problem of the combination of ferroelectric materials and Ga N HEMT devices.First of all,this paper introduces the process and analytical test method of HfZrO ferroelectric thin film in detail.Then HfZrO ferroelectric thin films were grown by atomic layer deposition(ALD)in our clean room of the team.The hysteresis loop of the real object is tested and its element types are tested by X-ray Photo-electronic Spectroscopy(XPS).After testing the samples,good polarization voltage hysteresis curve is obtained.The saturation polarization intensity is 10?C/cm~2,the residual polarization intensity is 5?C/cm~2,and coercive electric field is 0.4 MV/cm.Secondly,the effects of HfZrO ferroelectric thin film on the device were studied by Sentaurus TCAD.By extracting the parameters of HfZrO ferroelectric thin film,which was successfully deposited in this experiment,and adding them to the parameter list of device simulation software.The simulation results show that the addition of ferroelectric materials can improve the maximum current of the devices.Compared with Ga N HEMT devices without HfZrO ferroelectric thin film,the saturation current increases from 2.05 A/mm to2.14 A/mm,with an increase of 4.4%.The amplification region of the metal ferroelectric thin film Ga N HEMT device is significantly higher than that of the reference device,from–4 V to 1 V,to–6 V to 1 V.In addition,this paper concludes that there is a turning point of polarization direction in ferroelectric materials of MFS-Ga N HEMT,which is similar to the pinch point of MOSFET.Although the geometric size of ferroelectric materials is very long,the position that really enhances the carrier of devices is fixed,which is related to the voltage difference between gate and drain stage,as well as the inherent properties of ferroelectric materials.