Characterization of diamond films and their application for electrical devices

Thesis/Dissertation · Fri Dec 31 04:00:00 EST 1993

OSTI ID:106975

Shiomi, Hiromu

Diamond is considered a potentially useful material for high-frequency and high-power devices that operate under harsh conditions, because high-quality diamond has a high band gap, high breakdown voltage, high electron saturation velocity and a low dielectric constant. We therefore characterized diamond films in terms of morphology, optical properties and electrical properties and electrical properties for electrical device application. For the morphological characterization, we used atomic force microscopy (AFM) to investigate diamond films grown by the microwave plasma CVD method. We found that epitaxial growth decreases the surface roughness on the (100) surface, while it increases the surface roughness on the (110) surface. Additionally, we found the (100) surface of boron-doped films to e atomically smooth. In order to theoretically investigate growth morphology, we undertook atomistic calculations to determine the surface energy, ledge energies and adsorption energies of carbon on the diamond surface. We used an empirical potential energy function for carbon recently developed and verified by Tersoff. We found both the macroscopic features and the microscopic features of morphology consistent with the theoretical predictions. For the optical characterization, we used Raman spectroscopy to study the boron doping effect. Our finding was that boron doping shifts the diamond phonon peak toward the lower energy side and creates three other different peaks in the low energy range. For the electrical characterization, we conducted I-V, C-V and Hall effect measurements to determine the electrical properties of boron-doped diamond. We fabricated Schottky diodes and MESFETs with Al for Schottky contacts and Ti for ohmic contacts. Good rectifying properties were observed on the smooth epitaxial film grown on diamond (100). We observed basic transistor operation of the MESFETs, which indicates the feasibility of using this diamond for electrical devices.

• Research Organization: Stanford Univ., CA (United States)
• OSTI ID: 106975
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
42 ENGINEERING
CHEMICAL VAPOR DEPOSITION
DIAMONDS
ELECTRICAL PROPERTIES
ELECTRICAL TESTING
FIELD EFFECT TRANSISTORS
FILMS
MORPHOLOGY
OPTICAL PROPERTIES
PHYSICAL PROPERTIES
RAMAN SPECTROSCOPY
SCHOTTKY BARRIER DIODES
SEMICONDUCTOR DEVICES