Hall Factor in Ultrathin-Body Silicon-on-Insulator n-Type Metal-Oxide-Semiconductor Field-Effect Transistors

摘要

Hall factor (γ_H) is investigated experimentally in the ultrathin-body (UTB) silicon-on-insulator (SOI) n-type metal-oxide-semiconductor field-effect transistors (MOSFETs) with the SOI thicknesses (T_(SOI)) of less than 10nm. It is demonstrated experimentally for the first time that when T_(SOI) is thicker than 4.2 nm, γ_H decreases slightly with a reduction of T_(SOI), whereas when T_(SOI) is thinner than 4.2 nm, γ_H decreases drastically and becomes almost unity in T_(SOI) of 2.5 nm. The γ_H is calculated considering only phonon scattering. Then, calculated γ_H is compared with γ_H obtalned experimentally. In addition, it is found that in phonon scattering γ_H is determined dominantly by the intravalley scatterings of the twofold valleys. The dominance of the intravalley scatterings of the twofold valleys in the γ_H determination is attributed to the energy levels of subbands whereby most of the scatterings are the intravalley scatterings of the twofold valleys.