Ferroelectrics have great potential in the field of nonvolatile memory due to programmable polarization states by external electric field in nonvolatile manner.However,complementary metal oxide semiconductor compatibi...Ferroelectrics have great potential in the field of nonvolatile memory due to programmable polarization states by external electric field in nonvolatile manner.However,complementary metal oxide semiconductor compatibility and uniformity of ferroelectric performance after size scaling have always been two thorny issues hindering practical application of ferroelectric memory devices.The emerging ferroelectricity of wurtzite structure nitride offers opportunities to circumvent the dilemma.This review covers the mechanism of ferroelectricity and domain dynamics in ferroelectric AlScN films.The performance optimization of AlScN films grown by different techniques is summarized and their applications for memories and emerging in-memory computing are illustrated.Finally,the challenges and perspectives regarding the commercial avenue of ferroelectric AlScN are discussed.展开更多
In this paper,we reported a surface acoustic wave(SAW)device prepared and optimized by piezoelectric films containing AIN,AIScN(Sc-20 at%)and AIScN(Sc-30 at%)by reactive magnetron sputtering using Al and AISc alloy ta...In this paper,we reported a surface acoustic wave(SAW)device prepared and optimized by piezoelectric films containing AIN,AIScN(Sc-20 at%)and AIScN(Sc-30 at%)by reactive magnetron sputtering using Al and AISc alloy targets.We calculated the material intrinsic electromechanical coupling coefficient k_(t)^(2) of AlScN(Sc-20 at%)and AlScN(Sc-30 at%)which are much better than AIN.It can be explained by the lattice softening.Furtherly,the results were confirmed by transmission electron microscopy(TEM)observation of the microstructure.Then the SAW devices based on three thin films were tested by vector network analysis obtaining the device equivalent electro mechanical coupling coefficient k_(eff)^(2).The value of AIScN(Sc-20 at%)k_(eff)^(2),which equals to 1.94%,is higher than that of AIN and AIScN(Sc-30 at%)while the value of AIScN(Sc-30 at%)k_(t)^(2) is higher than that of others.It is shown in our study that the crystallinity and orientation of the material still have a greater impact on k_(eff)^(2) but it does not have influence on k_(t)^(2) in the actual device preparation process.展开更多
The discovery of ferroelectricity in aluminum scandium nitride(AlScN)thin films has garnered significant research inter-est,owing to the large remnant polarization,tunable coercive field,excellent thermal stability,hi...The discovery of ferroelectricity in aluminum scandium nitride(AlScN)thin films has garnered significant research inter-est,owing to the large remnant polarization,tunable coercive field,excellent thermal stability,high breakdown field,and compatibility with back-end-of-line processes of these thin films.These attributes make AlScN a highly promising can-didate for next-generation electronic device applications.Various techniques,such as reactive magnetron sputtering,radi-ofrequency sputtering,molecular beam epitaxy,metal-organic chemical vapor deposition,and pulsed laser deposition,have been employed to grow ferroelectric AlScN thin films.Critical growth parameters,including deposition atmosphere,precursor selection,and Sc concentration,strongly influence the ferroelectric properties,playing a crucial role in achieving high crystalline quality.This review critically examines the fabrication techniques used for producing ferroelectric AlScN thin films,focusing on the impact of different growth methods and process conditions on their properties.We aim to provide comprehensive guidance to assist future researchers in optimizing their process parameters to achieve the desired ferroelectric characteristics in AlScN thin films.展开更多
Developing multifunctional devices capable of on-demand task switching is crucial for highly integrated intelligent systems.We introduce a multifunctional ultraviolet(UV)photodetector(PD)based on an AlScN/GaN heteroju...Developing multifunctional devices capable of on-demand task switching is crucial for highly integrated intelligent systems.We introduce a multifunctional ultraviolet(UV)photodetector(PD)based on an AlScN/GaN heterojunction,featuring dynamically reconfigurable operating modes via bias voltages.At low bias voltages,it functions as a fast and highly sensitive UV PD(the specific detectivity reaching 9.37×10^(12) Jones),applied in high-speed imaging and optical communication.Interestingly,at higher bias voltages,the device exhibits a persistent photoconductivity effect.This behavior enables the effective emulation of biological synaptic plasticity,including key functions such as excitatory postsynaptic current,paired-pulse facilitation,and the transition from short-term memory to long-term memory.Leveraging this unique biascontrolled characteristic,we introduce a hardware-intrinsic encrypted optical imaging scheme by ingeniously combining the device’s distinct fast and slow photoresponse dynamics.Secure image access is achieved by employing a combination of synchronized optical inputs and dynamic biasing protocols as security keys.We demonstrate a single AlScN/GaN optoelectronic device platform for achieving reconfigurable multifunctionality and hardware-level encrypted imaging,holding significant potential for neuromorphic computing and highly secure information systems.展开更多
基金fundings of National Natural Science Foundation of China(No.T2222025,62174053 and 61804055)National Key Research and Development program of China(No.2021YFA1200700)+1 种基金Shanghai Science and Technology Innovation Action Plan(No.21JC1402000 and 21520714100)the Fundamental Research Funds for the Central Universities.
文摘Ferroelectrics have great potential in the field of nonvolatile memory due to programmable polarization states by external electric field in nonvolatile manner.However,complementary metal oxide semiconductor compatibility and uniformity of ferroelectric performance after size scaling have always been two thorny issues hindering practical application of ferroelectric memory devices.The emerging ferroelectricity of wurtzite structure nitride offers opportunities to circumvent the dilemma.This review covers the mechanism of ferroelectricity and domain dynamics in ferroelectric AlScN films.The performance optimization of AlScN films grown by different techniques is summarized and their applications for memories and emerging in-memory computing are illustrated.Finally,the challenges and perspectives regarding the commercial avenue of ferroelectric AlScN are discussed.
基金supported by the Innovation Funds of GRIMAT Engineering Institute Co.,Ltd.
文摘In this paper,we reported a surface acoustic wave(SAW)device prepared and optimized by piezoelectric films containing AIN,AIScN(Sc-20 at%)and AIScN(Sc-30 at%)by reactive magnetron sputtering using Al and AISc alloy targets.We calculated the material intrinsic electromechanical coupling coefficient k_(t)^(2) of AlScN(Sc-20 at%)and AlScN(Sc-30 at%)which are much better than AIN.It can be explained by the lattice softening.Furtherly,the results were confirmed by transmission electron microscopy(TEM)observation of the microstructure.Then the SAW devices based on three thin films were tested by vector network analysis obtaining the device equivalent electro mechanical coupling coefficient k_(eff)^(2).The value of AIScN(Sc-20 at%)k_(eff)^(2),which equals to 1.94%,is higher than that of AIN and AIScN(Sc-30 at%)while the value of AIScN(Sc-30 at%)k_(t)^(2) is higher than that of others.It is shown in our study that the crystallinity and orientation of the material still have a greater impact on k_(eff)^(2) but it does not have influence on k_(t)^(2) in the actual device preparation process.
基金supported by the China Postdoctoral Science Foundation(2023M742732)the Postdoctoral Fellowship Program of CPSF under(Grant No.GZC20241303)+2 种基金the Fundamental Research Funds for the Central Universities(XJSJ24100)the National Natural Science Foundation of China(Grant Nos.62404176,62025402,62090033,92364204,9226420,and 62293522)Major Program of Zhejiang Natural Science Foundation(Grant No.LDT23F04024F04).
文摘The discovery of ferroelectricity in aluminum scandium nitride(AlScN)thin films has garnered significant research inter-est,owing to the large remnant polarization,tunable coercive field,excellent thermal stability,high breakdown field,and compatibility with back-end-of-line processes of these thin films.These attributes make AlScN a highly promising can-didate for next-generation electronic device applications.Various techniques,such as reactive magnetron sputtering,radi-ofrequency sputtering,molecular beam epitaxy,metal-organic chemical vapor deposition,and pulsed laser deposition,have been employed to grow ferroelectric AlScN thin films.Critical growth parameters,including deposition atmosphere,precursor selection,and Sc concentration,strongly influence the ferroelectric properties,playing a crucial role in achieving high crystalline quality.This review critically examines the fabrication techniques used for producing ferroelectric AlScN thin films,focusing on the impact of different growth methods and process conditions on their properties.We aim to provide comprehensive guidance to assist future researchers in optimizing their process parameters to achieve the desired ferroelectric characteristics in AlScN thin films.
基金funded by the National Natural Science Foundation of China(Grant Nos.62374075,62274017,62174016,and 62074019)the Fundamental Research Funds for Central Universities of Jiangnan University(Grant Nos.JUSRP202504018 and JUSRP202501142)the Research and Practice Projects on Postgraduate Education and Teaching Reform of Jiangnan University(Grant No.YJSJGZD24_006).
文摘Developing multifunctional devices capable of on-demand task switching is crucial for highly integrated intelligent systems.We introduce a multifunctional ultraviolet(UV)photodetector(PD)based on an AlScN/GaN heterojunction,featuring dynamically reconfigurable operating modes via bias voltages.At low bias voltages,it functions as a fast and highly sensitive UV PD(the specific detectivity reaching 9.37×10^(12) Jones),applied in high-speed imaging and optical communication.Interestingly,at higher bias voltages,the device exhibits a persistent photoconductivity effect.This behavior enables the effective emulation of biological synaptic plasticity,including key functions such as excitatory postsynaptic current,paired-pulse facilitation,and the transition from short-term memory to long-term memory.Leveraging this unique biascontrolled characteristic,we introduce a hardware-intrinsic encrypted optical imaging scheme by ingeniously combining the device’s distinct fast and slow photoresponse dynamics.Secure image access is achieved by employing a combination of synchronized optical inputs and dynamic biasing protocols as security keys.We demonstrate a single AlScN/GaN optoelectronic device platform for achieving reconfigurable multifunctionality and hardware-level encrypted imaging,holding significant potential for neuromorphic computing and highly secure information systems.
