Fabrication And Carrier Scattering Mechanisms Investigation Of UTB Ge-OI MOSFETs

In 1956,Gordon Moore,the founder of the Intel,proposed Moore's law,which states that the density of transistors on an integrated circuit doubles every 18 months.In the fol-lowing decades,Moore's Law supported the development of the entire integrated circuit industry and became the benchmark for the development of semiconductor technology.However,as the critical size in the chip had been scaled down to nanometer,problems such as short channel effects and significant parasitic resistance had seriously hindered the de-velopment of Moore's Law.In order to continue Moore's Law,the current industry trys to overcomes the bottleneck either by using high-mobility channel materials or using novel device structures.In the search for high-mobility channel materials,germanium has al-ways been considered as a new channel material for transistors,because of its extremely high hole mobility and comparatively high electron mobility.In the search for novel de-vice structures,the ultra-thin semiconductor material on-insulator devices can effectively suppress the short channel effect,and has been widely used in high-performance proces-sors.Combining the advantages of high-mobility channel materials and the structure of semiconductor material on-insulator,the ultra-thin germanium on insulating layer(Ge-OI)MOSFETs can not only greatly improve the transistor performance,but also suppress the short channel effect.However,unlike silicon-on-insulator(SOI)devices,in Ge-OI MOS-FETs,as the thickness of the Ge layer decreases,the performance of the transistor will be severely degraded.One of its manifestations is that the mobility of the GeOI transistor is limited.In this article,the Ion-implantation Before Germanidation technique was used to fab-ricate Ge-OI pMOSFETs and nMOSFETs with different thicknesses;different back gate voltages was applied to control the depletion layer carrier density(Ndepl)in the GeOI chan-nel,and the Hall hole and electron mobilties at different temperature were measured for the Ge-OI MOSFETs with various Ge-OI layer thickness.As a result,the universal mo-bility has been obtained for both hole and electron in UTB Ge-OI p-and n-MOSFETs,respectively.Then,Eeff or Ns dependence of various scattering mechanisms in the Ge-OI channel was extracted by numerical methods.Further,verification of these results is confirmed by the good agreement between measured mobility and calculated total mobility combining those scattering mechanisms restricted ones.Thus,this method is confirmed effective for reflecting the impact of various carrier scattering mechanisms on the hole and electron mobility of Ge-OI pMOSFETs and nMOSFETs.In this article,Ge-OI pMOSFETs and nMOSFETs with different thicknesses have been fabricated,The Hall mobility of Ge-OI pMOSFETs and nMOSFETs were tested under dif-ferent temperatures.and depletion carrier density in the Ge-OI channel(Ndepl)was mod-ulated by applying different back gate voltages.The results show that holes and electrons in Ge-OI pMOSFETs and nMOSFETs also follow the universal mobility relationship,re-spectively;Then,the relationship between the mobility and Eeff or Ns corresponding to various scattering mechanisms in the channel of Ge-OI MOSFETs was extracted and sep-arated by numerical methods.And the influences of various scattering mechanisms on the carrier mobility characteristics have been quantitatively evaluated.Finally,by comparing the measured Hall mobility with the calculated theoretical mobility,it is proved that this method can effectively describe the mobility characteristics and carrier transport character-istics of ultra-thin Ge-OI p-and n-MOSFETs.