| 摘要 |
PURPOSE:To absorb a surge well and to reduce a chip area by composing it of a high impurity density first diffused region, a reverse conductivity type second diffused region formed deeply to be superposed with the periphery of the first region, and electrodes formed on the regions. CONSTITUTION:A protective diode of a semiconductor device formed on a semiconductor substrate 1 is composed of high impurity density one conductivity type first diffused region 2 formed on the substrate 1, a reverse conductivity type second diffused region 3 formed deeply in lower impurity density than the region 2, a first electrode 4 formed on the region 2, and a second electrode 6 formed at the periphery of the region 3. For example, the circular P-type first diffused region 2 is formed on a semi-insulating GaAs substrate 1, and the second diffused region 3 is so formed in a doughnut shape as to be superposed with the outer periphery of the region 2. Then, the first electrode 4 ohmically contacted with the central region of the region 2, and the second electrode 5 ohmically contacted with the outer periphery of the surface of the region 3 are formed.
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