SEMICONDUCTOR DEVICE

PURPOSE:To increase the crystal lattice temperature in a high electric field region locally, suppress the generation rate of hot electrons without lowering an element operating speed, and increase the reliability of the element, without making the element manufacturing process complicated, by irradiating light or electromagnetic wave from outside. CONSTITUTION:The drain diffusion layer 1 and source layer 2 of a MOSFET with single drain structure and formed wider in width than usual, and a contact is so formed that the drain Al wire 3 and source Al wire 4 may not overlap with the gate electrode 5. When infrared rays 10 are directed from above, if there are small gaps between the Al wires and the gate electrode, light reaches the diffusion layers by diffraction as the wavelength is long, and widening the diffusion layers increases the element size very slightly. Because of this, either the width of the source Al wire 4 is widened, or a contact forming mask is shifted to the drain side so that the source Al wire 4 may overlap with the gate. And, this structure prevents the temperature of the junction section from rising and makes it possible to maintain a better subthreshold characteristic.