Non-Alloyed Ohmic Contacts to n-GaAs Using Compositionally Graded In_xGa<1-x>As Layers : Semiconductors and Semiconductor Devices

概要

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Non-alloyed ohmic contacts to n-GaAs using compositionally graded In_xGa_<1-x>As layers grown by molecular beam epitaxy are studied. The carrier concentration reduction in the GaAs buffer layer due to low growth temperature is found to increase overall contact resistance for an n^+-InAs/In_xGa<1-x>As(x=1&arr;0)/GaAs structure. The lowest specific contact resistance(ρ_c) ever reported, 5×10^<-9> Ω・cm^2, is obtained with a 2×10^<19> cm^<-3> Si-doped structure grown at 450℃. A similar ρ_c value is also obtained when the InAs mole fraction is higher than 0.7. Using WSi as a contact metal, a refractory ohmic contact is realized in which ρ_c remains less than 2×10^<-7> Ω・cm^2 under annealing up to 800℃.
社団法人応用物理学会の論文
1988-09-20