Reducing the Cut-In Voltage of a Silicon Carbide/p-Silicon Heterojunction Diode Using Femtosecond Laser Ablation

We report on the fabrication of a low-cut-in voltage (a-SiC:H/Si) heterojunction diode using femtosecond laser ablation of silicon wafers in an octane environment. The femtosecond laser-induced plasma simultaneously reduces, carburizes, and hydrogenates the p-type silicon to develop a layer of hydrogenated silicon carbide (a-SiC:H) on top of the p-Si substrate. No reactive gases, source targets, dopants, or diffusion furnaces are required. The obtained current–voltage characteristics of the a-SiC:H/Si diode exhibit a cut-in voltage of 0.16 V, which is significantly lower than the rise potential of a typical SiC Schottky diode (0.75–1.6 eV) or the barrier potential (0.9–1 eV) of a typical p-Si/n-SiC diode. Moreover, this value is far less than the standard cut-in voltage of Si (0.7 V), or the typical body diode SiC MOSFETs (∼3 V). The achieved low cut-in voltage and the modest rectification ratio of the femtosecond laser-fabricated heterojunction diode demonstrate the promising potential of a rapid, facile, and cost-effective method for manufacturing efficient electronic devices.