A method for fabricating a semi-conductor wafer , the method comprising the steps of: a. providing a molten semi-conductor material, having a surface; b. providing a template , comprising a porous body comprising: i. a melt-ward surface ; ii. a back surface; iii. a first template region having a first heat extraction propensity; iv. a second template region having a second heat extraction propensity, which is greater than the first heat extraction propensity; c. providing a differential pressure regime such that pressure at at least a portion of the melt-ward surface is less than pressure at the molten semi-conductor material surface; and d. contacting the template melt-ward surface to the surface of the molten semi-conductor material for at least a portion of a contact duration, during which the melt-ward surface and the molten semi-conductor material are in contact with each other, and the differential pressure regime is provided, such that a body of semi-conductor material, solidifies upon the melt-ward surface , which formed body comprises: i. a first, thinner body region, which has a first thinner body average thickness, the first thinner body region having formed adjacent the first template region ; and ii. a second, thicker body region, which has a second thicker body average thickness, the second body region having formed adjacent the second template region , the second body average thickness being greater than the first body thickness. a. providing a molten semi-conductor material, having a surface; b. providing a template , comprising a porous body comprising: i. a melt-ward surface ; ii. a back surface; iii. a first template region having a first heat extraction propensity; iv. a second template region having a second heat extraction propensity, which is greater than the first heat extraction propensity; i. a melt-ward surface ; ii. a back surface; iii. a first template region having a first heat extraction propensity; iv. a second template region having a second heat extraction propensity, c. providing a differential pressure regime such that pressure at at least a portion of the melt-ward surface is less than pressure at the molten semi-conductor material surface; and d. contacting the template melt-ward surface to the surface of the molten semi-conductor material for at least a portion of a contact duration, during which the melt-ward surface and the molten semi-conductor material are in contact with each other, and the differential pressure regime is provided, such that a body of semi-conductor material, solidifies upon the melt-ward surface , which formed body comprises: i. a first, thinner body region, which has a first thinner body average thickness, the first thinner body region having formed adjacent the first template region ; and ii. a second, thicker body region, which has a second thicker body average thickness, the second body region having formed adjacent the second template region , the second body average thickness being greater than the first body thickness. i. a first, thinner body region, which has a first thinner body average thickness, the first thinner body region having formed adjacent the first template region ; and ii. a second, thicker body region, which has a second thicker body average thickness, the second body region having formed adjacent the second template region , the second body average thickness being greater than the first body thickness. <EOS>