Surface state density distribution of semiconducting diamond films measured from the Al/CaF2/i-diamond metal-insulator-semiconductor diodes and transistors

• DOI: 10.1063/1.365658
• Publication Date: 2002-07-26T13:52:43Z
• Authors: Young Yun; Tetsuro Maki; Takeshi Kobayashi
• Keywords: Surface States; MISFET

Diamond metal-insulator-semiconductor diodes and field-effect transistors (MISFETs) have been prepared using CaF2 gate insulator nondoped (in some cases, boron was doped) diamond homoepitaxial films. The resultant capacitance-voltage (C-V) curves drain current-drain voltage (ID−VD) strongly depended on the amount of oxygen contamination surface. From analyses C-V ID−VD curves, it found that induced surface states with two distribution peaks locating very near valence band edge at energy ∼1 eV from edge. Although fluorination oxygen-terminated proceeded to a certain extent during deposition elevated temperatures in vacuum, still allowed state formation about ∼1014/cm2 due uncompleted exchange by fluorine atoms easy penetration residual chamber through temperatures. Reduced-oxygen process passivation hydrogen (hydrogenation) room temperature greatly improved stability, consequently, density reduced ∼1012/cm2 eV. In this manner, effective hole mobility ∼10 cm2/V s obtained MISFET, which can be well compared Hall 35 s.