PNP transistor structure resistant to total dose irradiation

Abstract

The invention discloses a PNP transistor structure resistant to total dose irradiation. The PNP transistor structure comprises a p-type substrate and an n-well arranged in the p-type substrate. A second p+ region spaced from the n-well is arranged in the p-type substrate. A first p+ region and an n+ injection region are arranged in the n-well at an interval. An annular polycrystalline silicon gridis arranged outside the first p+ region in a surrounding mode. Compared with a PNP transistor prepared through the conventional CMOS (complementary metal oxide semiconductor) process, the annular polycrystalline silicon grid is adopted to surround the first p+ region, so that the formation of p / n+ junctions caused by the thick-field oxygen in the prior art is completely avoided. The total dose radiation effect is eliminated. As a result, the total dose irradiation resistance of the CMOS band gap reference reaches 300 krad (Si) under the dosage rate of 50 rad(Si) / s.

Description

technical field [0001] The invention relates to the field of radiation reinforcement against total dose radiation effect, in particular to a PNP transistor structure against total dose radiation. Background technique [0002] When the device is continuously exposed to ionizing radiation (such as gamma rays and X-rays, etc.), the total dose radiation effect will occur. Under the condition of total dose radiation, the ionization in the silica medium produces a certain number of electron-hole pairs. When there is an electric field, oxide trap charges and interface state charges are accumulated in silicon dioxide, thereby affecting the performance of the device. [0003] CMOS bandgap reference is a widely used module in CMOS analog integrated circuits. Its performance depends on the pn junction characteristics in the forward biased state. Bandgap Reference Circuits As feature sizes in CMOS technology get smaller, circuits become more sensitive to total dose radiation. The ma...

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Problems solved by technology

Since the radiation-induced excess electron concentration under the field oxygen layer 3 depends on the cumulative radiation dose, the I / V characteristics of the overall diode will have a considerable drift in the radiation environment, thereby causing the reference output voltage to be unstable.

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