Implications of atomic-level manipulation on the Si(100) surface: From enhanced CMOS reliability to molecular nanoelectronics

The ultra-high vacuum scanning tunneling microscope (UHVSTM) has been used to induce desorption of H from the Si(100)-2X1:H surface with atomic-level precision. The study of the desorption mechanism led to the discovery of a substantial isotope effect between H and D, which has recently been employed to minimize hot electron degradation at the Si/SiO₂ interface in conventional complementary metal-oxide-semiconductor (CMOS) circuits. This paper will reveal secondary ion mass spectroscopy (SIMS) data that show a direct correlation between D incorporation at this interface and transistor lifetime. D incorporation can be enhanced via high-pressure processing, which has led to lifetime improvements in excess of 700× for Samsung's latest 0.18 μm, 1.5 V CMOS technology. In addition to enhancing current integrated circuits, UHVSTM-induced hydrogen desorption has aided the development of nanoelectronics on the molecular-size scale. Feedback-controlled lithography (FCL) has refined the desorption process to the point where templates of individual dangling bonds can be generated in arbitrary geometries. The chemical contrast between dangling bonds and H-passivated Si is then utilized to isolate individual copper phthalocyanine (CuPc) and C₆₀ molecules on the Si(100) surface. Following isolation, STM spectroscopy has characterized the mechanical and electrical properties of these molecules with intra-molecular precision.