Among wide-bandgap semiconductor materials, diamond presents a number of benefits including improved breakdown voltage, carrier mobility, thermal conductivity, and thermal stability. N-type doping of diamond is commonly achieved using phosphorus but with limited success at high concentrations. This is particularly true for the (100) surface orientation of diamond which is preferred for device manufacturing. As a result, electrical contacts exhibit high specific contact resistances, diminishing the practicality of n-type diamond semiconductors.
Researchers at Arizona State University have developed a method for preparing high-performance electrical contacts for n-type diamond even at phosphorus concentrations less than 3E19 cm-3. Demonstrated specific contact resistances were on the order of 1E3 Ω·cm2. This is accomplished by an interstitial nanostructured carbon (nanoC) layer with high nitrogen concentration, contacted by conventional Ti/Pt/Au metallurgy or other optimized means. The nanoC layers are economically prepared by plasma-enhanced chemical vapor deposition (PECVD) with high uniformity over large areas. Diamond surface orientations compatible with this method include (100) and (111).
• Diamond-based solid-state devices
• Power electronics
• High-temperature electronics
Benefits and Advantages
• Reduces contact resistance while allowing flexibility in both phosphorus doping concentration and diamond surface orientation
• High reproducibility and compatibility with diamond photolithography
• High stability at temperatures up to 550°C