There is disclosed a photovoltaic conversion device constructed using a
p-type crystalline silicon substrate 404 doped with boron, which
comprises a bulk substrate region 404, regions other than the bulk
substrate region including an n-type region 403a joining to a light
receiving surface of the bulk surface region, a BSF region 405 joining to
a back surface of the bulk surface region, wherein with regions other
than the bulk substrate region 404 being removed, when a minority carrier
diffusion length of the bulk substrate region 404 is measured from the
light receiving surface of the bulk surface region, 0.5<(L1/Lpeak)is
satisfied, where L1 is a minority carrier diffusion length at an
arbitrary measuring area of the light receiving surface of the bulk
surface region, and Lpeak is a diffusion length corresponding to a
maximum peak on the side of higher diffusion length of a histogram, the
histogram being formed from data obtained when a minority carrier
diffusion length of the light receiving surface of the bulk surface
region is measured at a plurality of measurement areas. This structure
can reduce influence of impurities such as Fe, and enhances utilization
efficiency of silicon ingots. With this structure, a photovoltaic
conversion device with high photovoltaic conversion efficiency can be
realized.