Design of Si/SiGe heterojunction complementary metal-oxide-semiconductor transistors

An optimized Si/SiGe heterostructure for complementary metal-oxide-semiconductor (CMOS) transistor operation is presented. Unlike previous proposals, the design is planar and avoids inversion of the Si layer at the oxide interface. The design consists of a relaxed Si0.7Ge0.3 buffer, a strained Si quantum well (the electron channel), and a strained Si1-xGex (0.7 > x > 0.5) quantum well (the hole channel). The channel charge distribution is predicted using 1-D analytical model and quantum mechanical solutions, Transport is modeled using 2-D drift-diffusion and hydrodynamic numerical simulations. An almost symmetric performance of p- and n-transistors with good short-channel behavior is predicted. Simulated ring oscillators show a 4- to 6-fold reduction in power-delay product compared to bulk Si CMOS at the 0.2-mu m channel length generation.