| 摘要 |
A method for fabricating a solid-state image pick-up device changes part of the constituent elemental Si into the n-type impurity phosphorus P, thus changing the substrate to an n-type, by atomic transmutation through neutron irradiation of a p-type silicon Si wafer, and thus produces a Si substrate with a resistivity rho s of 10 to 100 ohm-cm. or preferably 40 to 60 ohm-cm. A solid-state image pick-up device with a plurality of photosensors and vertical and horizontal shift registers as set forth above is then fabricated using the resulting Si substrate. In the preferred process, the silicon substrate can be obtained by irradiating a wafer sectioned from a crystal grown by the MCZ method, for instance, with neutrons as described before until it has the required resistivity rho s. This silicon substrate is preferably of a p-type before neutron irradiation, that is, in the crystal growth state, and its resistivity rho o is then ten or more times higher (100 ohm-cm. or more) than that rho s obtained following neutron irradiation. For instance, if rho s is to be 40 to 50 ohm-cm., rho o should be 680 to 1180 ohm-cm. Then, n-type impurities, e.g. phosphorus P are generated by neutron irradiation to convert the silicon substrate to n-type with a low resistivity of rho s=10 to 100 ohm-cm., or of 40 to 50 ohm-cm. |
