%0 Journal Article
%A San Andrés Serrano, Enrique
%T High-k gate stacks on low bandgap tensile strained Ge and GeSn alloys for field-effect transistors
%D 2015
%@ 1944-8244
%U https://hdl.handle.net/20.500.14352/34692
%X We present the epitaxial growth of Ge and Ge_(0.94)Sn_(0.06) layers with 1.4% and 0.4% tensile strain, respectively, by reduced pressure chemical vapor deposition on relaxed GeSn buffers and the formation of high-k/metal gate stacks thereon. Annealing experiments reveal that process temperatures are limited to 350°C to avoid Sn diffusion. Particular emphasis is placed on the electrical characterization of various high-k dielectrics, as 5nm Al_(2)O_(3), 5nm HfO_(2) or 1nm Al_(2)O_(3)/4nm HfO_(2), on strained Ge and strained Ge_(0.94)Sn_(0.06). Experimental capacitance-voltage characteristics are presented and the effect of the small bandgap, like strong response of minority carriers at applied field, are discussed via simulations.
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