Boron-doped Homoepitaxial Diamond Research Articles

High-temperature Schottky diodes with thin-film diamond base

High-temperature (500-580 degrees C) current-voltage (I-V) characteristics of gold contacts to boron-doped homoepitaxial diamond films prepared using a plasma-enhanced chemical vapor deposition (CVD) method are described. Schottky diodes were formed using gold contacts to chemically cleaned boron-doped homoepitaxial diamond films. These devices incorporate ohmic contacts formed by annealing Au(70 nm)/Ti(10 nm) layers in air at 580 degrees C. The experiments with homoepitaxial diamond films show that the leakage current density increases with the contact area. This implies that a nonuniform current distribution exists across the diode, presumably due to crystallographic defects in the diamond film. As a result, Au contacts with an area >1 mm/sup 2/ are essentially ohmic and can be used to form back contacts to Schottky diodes. Schottky diodes fabricated in this matter also show rectifying I-V characteristics in the 25-580 degrees C temperature range. >

The effect of surface treatment on the electrical properties of metal contacts to boron-doped homoepitaxial diamond film

Both doped and undoped homoepitaxial diamond films were fabricated using microwave plasma-enhanced chemical vapor deposition (CVD). The conductivity of the diamond film is strongly affected by the surface treatment. In particular, exposure of film surface to a hydrogen plasma results in the formation of a conductive layer which can be used to obtain linear (ohmic) I-V characteristics of the Au/diamond contacts, regardless of the doping level. It is shown how the proper chemical cleaning of the boron-doped homoepitaxial diamond surface allows the fabrication of Au-gate Schottky diodes with excellent rectifying characteristics at temperatures of at least 400 degrees C. >

High temperature Schottky diodes with boron-doped homoepitaxial diamond base

We report the first high temperature operation of thin film diamond based semiconductor devices. Boron-doped homoepitaxial diamond films were grown by microwave plasma assisted chemical vapor deposition using insulating natural diamond substrates. The diamond nature of the films was confirmed by several analytical techniques. Excellent rectifying characteristics were obtained for Au-gate Schottky diodes with homoepitaxial diamond base in the 26–583°C temperature range. Surface cleaning of the films was found to be a key step of the fabrication process.