Abstract: It is an object of the present invention to provide a silicon solar cell with n+pp+ BSF structure using solar grade silicon substrate, having a life time close to the initial level of the substrate. The solar cell of the present invention is produced by a back side boron diffusion step for diffusing boron on a back side of the substrate, a front side phosphorus diffusion step for diffusing phosphorus on a front side of the substrate, a low-temperature annealing step for annealing the substrate at 600° C. or lower for 1 hour or more, and an electrode firing step carried out at a peak temperature of 700° C. or lower for 1 minute or less, carried out in this order.

Abstract: It is an object of the present invention to provide a silicon solar cell with n+pp+ BSF structure using solar grade silicon substrate, having a life time close to the initial level of the substrate. The solar cell of the present invention is produced by a back side boron diffusion step for diffusing boron on a back side of the substrate, a front side phosphorus diffusion step for diffusing phosphorus on a front side of the substrate, a low-temperature annealing step for annealing the substrate at 600° C. or lower for 1 hour or more, and an electrode firing step carried out at a peak temperature of 700° C. or lower for 1 minute or less, carried out in this order.

Abstract: A detector for the moving velocity of a magnetic head of a magnetic disc memory device by electrically processing a position signal of the magnetic head, which includes a circuit for differentiating the position signal, means for rectifying the differentiating circuit, a circuit for sampling-hold of the rectified signal, a phase-shifter for delaying the position signal and means for generating a timing pulse signal to determine the timing for sampling, with the phase delaying characteristic of the transfer function of the differentiating circuit and the phase-shifting circuit being substantially coincided.