Study Of The E（k）～k Relation Of Valenced-Band Structure For Strained Ge/Si_1-xGe_x

For decades,after the size of CMOS device getting into the sub-micron,deep sub-micron areas,the traditional material and geometries used in the device have been limited by the property of their own.Increasing of electronic and hole mobility made by strain Ge technology absurd absorbs people’s attention more and more..By the advantages of the strained Ge,on the same congdition of geometries,the effection can be the same as it made by reducing the scale of the device.So the property of the device made under this condition has been developt a lot.And the cost of the reduces a lot too.Above all,the researchers focur on the strained Ge technologe.The research of the band structure can study the physical parameters of the concentration of the carriers and electric conductivity starting with the property of the strained Ge.However,the research of the theory of the strained Ge band structure is lagger than the research of using it.And in board,there is few reports about the band structure of strained Ge band structure.So the band structure material strainedThere is a study about the lattice structure of Ge in this paper,based on the band structure characteristics,the E-k relation of valence band structure for relaxed Ge is studied.According the E-k relation,the hole effective masses in the direction of[100]and[111]are calculated.The carrier mobility is also discussed.Given strain effects of semiconductor materials,the tensors model and matrix form of strain for strained Ge are obtained.The classical theories of semiconductor bandgap structure,such as pseudopotential method,tight-bonding method and k·p perturbation method,are studied.K·p perturbation method is chosen to calculate the valence band structure of strained Ge according to the characteristics of Ge bandgap structure.Based on the Schrodinger wave equation,with the frame of K·P theory,the E(k)-k relation has been derived by taking strained Hamiltonian perturbation and deformation of potential into account.In terms of the model of Ge valence band above,some corresponding numerical calculation work is also done in order to attain the E～k expression of valence band of Ge on SiGe.The changing of valence band and the effective mass in each orientation are also obtained.Compared to the results in some references,the calculation was right,and the trend of valence band’s changing under strain are also correct.