Ultra-high-voltage (UHV) junction field-effect transistors (JFETs) embedded separately with the lateral NPN (JFET-LNPN),and the lateral and vertical NPN (JFET-LVNPN),are demonstrated experimentally for improving the electrostatic discharge (ESD) robustness.The ESD characteristics show that both JFET-LNPN and JFET-LVNPN can pass the 5.5-kV human body model (HBM) test.The JFETs embedded with different NPNs have 3.75 times stronger in ESD robustness than the conventional JFET.The failure analysis of the devices is performed with scanning electron microscopy,and the obtained delayer images illustrate that the JFETs embedded with NPN transistors have good voltage endurance capabilities.Finally,the internal physical mechanism of the JFETs embedded with different NPNs is investigated with emission microscopy and Sentaurus simulation,and the results confirm that the JFET-LVNPN has stronger ESD robustness than the JFET-LNPN,because the vertical NPN has a better electron collecting capacity.The JFET-LVNPN is helpful in providing a strong ESD protection and functions for a power device.