We conducted a repetitive process for tiling freestanding substrates made from one identical seed crystal. After the mechanical polishing of both sides of the tiled substrates over the inch-sized area, the boundaries between the constituent substrates were barely recognized. By repeating the tiling process, we succeeded in fabricating several freestanding wafers with a size of 1.5 in. (area of approximately 20 × 40 mm2). For this wafer size range, we found that non-uniformities in the morphology, as well as the growth rate, became remarkable. By qualitative comparison between the numerical predictions and the experimental observations, we discussed the dominant factors that control the non-uniformity.
► Inch size wafers of single-crystal diamond are fabricated. ► Such large size wafers are processed to enlarge the wafer size moreover. ► Finally, 1.5 inch size freestanding wafers are fabricated. ► Possible reasons of non-uniformity in impurity concentration are discussed.