Reliability of High-Voltage LSI´s Made Using the Dielectric Isolation Process

A high-voltage subscriber-line interface large-scale integrated (LSI) circuit with high reliability is developed. To realize 350 V blocking voltage, this high-voltage LS1 is fabricated using an epitaxial passivated integrated circuit (EPIC) dielectric isolation technology and a field plate technique. Certain instabilities, such as leakage current increase and breakdown voltage decrease, has been reduced by using an n⁺buried layer and a field-plate structure for a low-voltage junction in the high-voltage device. This technique produces high-voltage LSI´s with long-term stability and reliability of less than 20 FIT. This is confirmed by results of a 125°C, 10 000-h operating test. It is confirmed that highvoltage LSI´s made by the EPIC dielectric isolation process are as highly reliable as low-voltage conventional bipolar LSI´s.