Next methods deposit sacrificial layer 3441 on contact layer 3440 as illustrated in FIG. 34C. Sacrificial layer 3441 may be in the range of 10 to 500 nm thick, for example, and be formed using conductor, semiconductor, or insulator materials such as materials described further above with respect to contact layer 3430, semiconductor layers 3420 and 3425, and insulator layer 3435.