Enhanced electrical characteristics of Zr/diamond Schottky barrier diode with cerium hexaboride interfacial layer

To fabricate a performance-enhanced Schottky barrier diode (SBD) on a diamond, a cerium hexaboride (CeB₆) interfacial layer was introduced between the diamond and the Zr/Au electrode. The inserted CeB₆ layer was characterized using X-ray photoelectron spectroscopy. Introducing the CeB₆ layer significantly improved the performance of the diamond SBD compared with a sample without the layer. The ideality factor (n)/SBH (Φ_B) values of the SBD with and without the CeB₆ interlayer were 2.24/1.92 eV and 2.82/1.65 eV, representing an improvement of 20.5% and 16.4% for the ideality factor and Schottky barrier height, respectively. The reverse breakdown voltage increased from −86 to −110.5 V, indicating an improvement of 28.5% for breakdown voltage. Additionally, the reverse current of the SBD with CeB₆ was suppressed, making it more reliable and stable than that without CeB₆ before the breakdown threshold. The carrier concentration and depletion layer width were increased from 1.135 × 10¹⁴ cm⁻³ and 206.7 nm to 2.646 × 10¹⁴ cm⁻³ and 227.6 nm, respectively, with the introduction of CeB₆. These results demonstrate the advantages of inserting of CeB₆ in vertical diamond SBDs and show the potential of SBDs for future power rectifiers.