Fabrication and characterization of diamond (100) p+-i-n+ diodes with heavily nitrogen-doped films

N-type diamond-based diodes are currently faced with challenges associated with high contact resistance at the interface of the metal and n-type semiconductor. To address this issue, we attempt to reduce the contact resistance by utilizing a heavily nitrogen-doped film with a nitrogen impurity concentration of 8.0 × 1020/cm3. In the fabricated p+-i-n+ device, we observed a rectification ratio of six orders of magnitude at ±10 V and a built-in voltage of 3.5 V. These findings mark a significant milestone as they represent the first-ever report of room-temperature operation in a device that utilizes a heavily nitrogen-doped film as the n+-layer. This breakthrough has effectively overcome the high contact resistance in n-type diamond semiconductors. The implications of our findings are substantial, as they expand the potential of nitrogen in diamond power devices.