Diamond electronics can provide significant advances in electronics due to exceptional properties such as large bandgap energy, high thermal conductivity, a low dielectric constant, and resistance to radiation. Obtaining n-type and p-type electronic character through impurity doping is necessary for diamond electronics and optoelectronics. Manufacturing of diamond electronic devices based on (100) oriented substrates is preferred due to enhanced electronic properties and less expensive fabrication. While p-type diamonds can be readily obtained through boron doping, n-type doping is still challenging, especially for (100) oriented diamond surfaces. Most electronically suitable n-type diamond devices are still prepared from (111) wafers, which is more expensive and limits the device properties and wafer size. Therefore, there is a need for an effective and economical method for n-type doping of (100) oriented diamond surfaces.
Researchers at Arizona State University have developed a novel growth process for phosphorus incorporation in n-type doping of diamonds with (100) and related surface orientation. In combination with plasma-enhanced chemical vapor deposition (PECVD), this method uses a pulsed deposition technique to enhance phosphorus incorporation in epitaxial diamond layers grown on (100) oriented substrates. By cycling or pulsing the plasma and controlling gas flow, increased phosphorus doping occurs at the higher local temperature of the wafer. Repetitive growth pulses achieve significant phosphorus incorporation and high temperature growth pulses can increase the concentration of phosphorus incorporation to achieve optimal n-type electrical properties. Additionally, precise doping concentrations and diamond characteristics can be achieved through regulating the gas flow rates, pressure, and plasma power.
- Diamond electronics
- Diamond radiation detectors
- Diamond UV optoelectronics
Benefits and Advantages
- Increased Doping Efficiency – High temperature growth pulses can increase the concentration of phosphorus incorporation to achieve n-type electrical properties.
- Increased Thermal Control - The equipment allows for increased control of the substrate local temperature to maximize phosphorous doping efficiency.
- Improved Quality - Eliminates need for surface polishing and more elaborate preparation.
- Adaptable - Variations of the gas flow rates, pressure, and plasma power can alter the doping concentration and refine the n-type doping characteristics.
- Less Expensive - Most electronic grade n-type diamonds are prepared on (111) oriented diamond which requires a more elaborate processing resulting in higher cost and smaller substrates. With electronic grade n-type (100) diamond, discrete semiconductors for power electronics, radiation detectors and UV optoelectronics could be prepared more economically.
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