| 摘要 |
PURPOSE: To enhance the clamp effect and reduce the series resistance of a clamp diode by forming a trench, expanding from the extrinsic base of a bipolar transistor to the collector to form a partly vertical clamp diode. CONSTITUTION: A transistor 30 comprises a P<-> -Si substrate 32, N<+> -buried layer 34, an isolated region 36, P<+> -channel stop 38, N<-> -collector 40, P-active base 42, N<+> -emitter 44, N<+> -polysilicon emitter contact 46, P<+> -extrinsic base 48, a Pt silicide layer 50 which forms a Schottky barrier diode with the collector 40 and ohmic contact with the extrinsic base 48, an N<+> -collector contact 52, a collector metal contact 54 and an insulation oxide 56. This increases the diode area, reduces the distance to the buried layer to thereby reduce the series resistance of the diode and enhance the clamp effect. |
