Abstract
In recent years, because of the rapid growth in the applications in power management, consumer electronics, drive circuit and automotive electronics, etc., high-voltage process was widely used in integrated circuits (ICs). However, in the reliability of the IC products, Electrostatic discharge (ESD) design is a very important indicator. Because of the high-voltage process and structure are more complicated compared with low voltage components, in order to meet multiple application voltage, that the ESD protection design is also more difficulty. This thesis will base on high-voltage BCD process to consider the IC manufacturing process, analysis and comparison of device characteristics in the ESD applications. Many elements can be used as electrostatic discharge protection in high-voltage IC process. For example: bipolar junction transistor (BJT), silicon controlled rectifier (SCR) and high voltage MOS transistor (HV-MOS). Among them, the SCR has a lower turn-on resistance such that it can provide good ESD protection much more efficient than other elements in a small layout area. Therefore, the SCR devices are often used in ESD protection design. This thesis also particular emphasized in the discussion of the SCR. Although HV SCR is often used in ESD protection design, its high trigger voltage and low holding voltage characteristics will be limited to the application of high voltage ESD protection. In order to trigger the SCR early, usually requires additional circuitry. The most commonly used is a gate and substrate trigger. Pulling away the distance between the anode and cathode can be effectively solve the latch-up problem of holding too low for SCR device. This thesis only modified a single parameter, to make the holding voltage increase from 4V to 17.5V without changing the original trigger voltage. The SCR area is relatively large when distance was increased. In this thesis a new structure is proposed that can effectively improve the SCR holding voltage. The holding voltage can be increased from 14V to 23V without increasing the device area. In addition to SCR, another small area high ESD robustness device is diode. Because of its single-directional characteristics for ESD protection, diode can only be used in forward mode operation. This thesis also discusses high-efficiency and high-frequency Junction Barrier Schottky diode for the HV-PMIC which is used in the forward pre-charge. Because this JBS diode connects to IC pad, it will encounter ESD stress. Therefore, we propose a new JBS diode structure embedded an Lateral PNP transistor to achieve +/- ESD self-protect. The new JBS can meet industry standards and pass ESD stress for HBM ±2KV and MM ±200V. This thesis present innovative contributions and effective improvement of ESD protection devices on actual HV integrated process.