High-k Gate Stacks on Low Bandgap Tensile Strained Ge and GeSn Alloys for Field-Effect Transistors

作者：Wirths Stephan^*; Stange Daniela; Pampillon Maria Angela; Tiedemann Andreas T; Mussler Gregor; Fox Alfred; Breuer Uwe; Baert Bruno; San Andres Enrique; Nguyen Ngoc D; Hartmann Jean Michel; Ikonic Zoran; Mantl Siegfried; Buca Dan

来源：ACS Applied Materials & Interfaces, 2015, 7(1): 62-67.

DOI：10.1021/am5075248

• strained Ge
• GeSn
• high-k dielectrics
• low bandgap alloys
• field effect transistor

We present the epitaxial growth of Ge and Ge0.94Sn0.06 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 degrees C to avoid Sn diffusion. Particular emphasis is placed on the electrical characterization of various high-k dielectrics, as 5 nm Al2O(3), 5 nm HfO2, or 1 nmAl(2)O(3)/4 nm HfO2, on strained Ge and strained Ge0.94Sn0.06. 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.

• 出版日期2015-1-14
• 单位中国地震局