A method for manufacturing a photodiode array includes providing a semiconductor substrate having first and second main surfaces opposite to each other. The semiconductor substrate has a first layer of a first conductivity proximate the first main surface and a second layer of a second conductivity proximate the second main surface. A via is formed in the substrate which extends to a first depth position relative to the first main surface. The via has a first aspect ratio. Generally simultaneously with forming the via, an isolation trench is formed in the substrate spaced apart from the via which extends to a second depth position relative to the first main surface. The isolation trench has a second aspect ratio different from the first aspect ratio.