Identification of the Current Transport Mechanism in a Vertical Zr/LaB₆/p-Diamond Schottky Barrier Diode for Low-Power Highly Sensitive Temperature Sensor

We proposed a low-power highly sensitive temperature sensor based on a diamond Schottky barrier diode (SBD) with an inserted lanthanum hexaboride (LaB6) interlayer at the Zr/diamond interface. The Zr/LaB6/p-diamond SBD exhibits excellent thermal stability with rectification ratios higher than $10^{{10}}$ in a wide temperature range of 298–573 K. The Schottky barrier height (SBH) increases, whereas the ideality factor decreases with increasing temperature. This SBD delivers a high SBH of 2.06 eV and an ideality factor close to 1 at 573 K. In addition, a thermionic emission (TE) theory assumes the Gaussian distribution of SBH to be the dominating current transport mechanism (CTM) for Zr/LaB6/diamond SBD, due to the existence of SBH inhomogeneities at Zr/diamond interface. Meanwhile, the extracted values of the mean SBH and Richardson constant are 2.74 eV and 82.43 A/cm $^{{2}}~\cdot ~\text{K}^{{2}}$ , respectively, which are much closer to their theoretical values of 2.72 eV and 96 A/cm $^{{2}}~\cdot ~\text{K}^{{2}}$ , respectively. Furthermore, a high thermal sensitivity of 5.1 mV/K is obtained for a temperature sensor based on this SBD. Our results suggest the great potential of adopting this SBD structure for high-performance temperature sensors.