The invention relates to a resist for electron beam lithography and to a process for producing photomasks for optical lithography. Turbulence accelerators, such as dummy battery units or the like, are provided in a position on the uppermost-stream side of the enclosure in which air flows in the direction of arrangement of the battery modules. The side-holes cause an asymmetric stress across the core of the sensor creating a birefringent sensor. First and second LD regions are in the substrate and laterally extend between the channel region and the source or drain regions respectively, each with a portion thereof not disposed under the first and second spacers nor under the conductive gate, and each with a dopant concentration less than that of the source or drain regions.