Capacitance-voltage measurements on metal-SiO2-diamond structures fabricated with (100)- and (111)-oriented substrates

• Published in: IEEE transactions on electron devices Vol. 38; no. 3; pp. 619 - 626
• Main Authors: GEIS, M. W, GREGORY, J. A, PATE, B. B
• Format: Journal Article
• Language: English
• Published: New York, NY Institute of Electrical and Electronics Engineers 01.03.1991
• Subjects: Applied sciences; Compound structure devices; Electronics; Exact sciences and technology; Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices; Depletion mode; Semiconductor materials; Crystal orientation; Interface electron state; MIS structure; Diamond; Energy diagram; Characterization; Field effect transistor; p channel; Silicon Oxides; P type conductivity; Voltage capacity curve
• ISSN: 0018-9383; 1557-9646
• DOI: 10.1109/16.75174

Metal-SiO2-diamond structures fabricated using (100)- or (111)-oriented substrates of type IIb natural diamond (a p-type semiconductor) are discussed. The SiO2-diamond interface was electrically characterized by measuring the capacitance between the metal electrode and the diamond substrate as a function of bias voltage. Capacitance-voltage (C-V) characteristics were measured for various SiO2 thicknesses and substrate temperatures, with and without exposure to ultraviolet light. For (100)- oriented diamond substrates, the SiO2-diamond interface is of device quality, and the minimum conduction-band energy of diamond is found to be 1.4 eV below that of SiO2. For (111)-oriented substrates this energy for diamond is 1.6 eV above that for SiO2 and 0.7 eV above the vacuum level. From these results, it appears that useful depletion-mode, metal-SiO2- diamond FETs can be made on (100)-oriented diamond substrates and that (111)-oriented substrates may be of value as cold cathodes. (I.E.)