Abstract: A charge-coupled device capable of attaining excellent performance with a single-layer gate electrode structure is obtained. This charge-coupled device, having a single-layer gate electrode structure, comprises a gate insulator film formed on a semiconductor substrate, a plurality of partitions, consisting of an insulator, formed on the gate insulator film, and concave gate electrodes, arranged between adjacent ones of the partitions, having side surfaces formed along side portions of the partitions. Thus, when the partitions are formed with a width of not more than the minimum critical dimension of lithography, the interval between the adjacent gate electrodes is not more than the minimum critical dimension of lithography.

Abstract: Threshold voltage fluctuation in upper corner portions of a trench isolation is inhibited by rounding upper corner portions of the trench by thermal oxidation, introducing a first impurity into both upper corner portions of the trench and heat-treating the semiconductor substrate. Embodiments include increasing the threshold voltage in the upper corner portion of the trench in an n-channel transistor, previously increased by rounding oxidation, and introducing a p-type impurity, thereby canceling the threshold voltage reduction resulting from diffusion of the impurity during heat-treating the semiconductor substrate. In a p-channel transistor, the threshold voltage in the upper corner portion of the trench is increased by rounding oxidation thereby canceling the threshold voltage reduction resulting from introduction of the p-type first impurity into both upper corner portions of the trench.

Abstract: A method of fabricating a semiconductor device capable of inhibiting a threshold voltage from fluctuation in upper corner portions of a trench isolating a first conductivity type channel region and a second conductivity type channel region from each other is obtained. This method of fabricating a semiconductor device comprises steps of forming a trench for isolating a first transistor and a second transistor from each other on a semiconductor substrate, rounding upper corner portions of the trench by thermal oxidation, introducing a first impurity into both upper corner portions of the trench and heat-treating the semiconductor substrate. Therefore, when a p-type impurity is employed as the first impurity, for example, the threshold voltage in the upper corner portion of the trench is previously increased in an n-channel transistor due to rounding oxidation and introduction of the p-type impurity.

Abstract: A method of manufacturing a semiconductor device capable of suppressing increase of a leakage current resulting from a high-temperature heat treatment is obtained. In this manufacturing method, an impurity region is formed by selectively ion-implanting an impurity into the main surface of a semiconductor substrate. The impurity region is activated by performing a high-temperature heat treatment. The semiconductor device is recovered from crystal defects resulting from the high-temperature heat treatment by performing a low-temperature heat treatment after performing the high-temperature heat treatment. According to this manufacturing method, the semiconductor device is recovered from the crystal defects resulting from the ion implantation by the high-temperature heat treatment, and recovered from the crystal defects resulting from the high-temperature heat treatment by the low-temperature heat treatment.

Abstract: A pair of source/drain regions are formed on a semiconductor substrate at a predetermined interval. A gate insulator film is formed on the semiconductor substrate between the source/drain regions of the pair. A gate electrode is formed on the gate insulator film. A film for covering the gate electrode and the source/drain regions has a low permeability against water and a hydroxide group, and has a thickness greater than 3 nm and less than 5 nm.