US Patent 7544984 Gettering using voids formed by surface transformation

One aspect of this disclosure relates to a memory device, comprising at least one gettering region, a memory array, a plurality of word lines and bit lines, and control circuitry. The gettering region is formed in a semiconductor substrate. The gettering region includes a precise arrangement of precisely-formed voids to getter impurities from a crystalline semiconductor region of the substrate. The memory array is formed in the crystalline semiconductor region, and includes a plurality of memory cells formed in rows and columns, and at least one transistor for each of the plurality of memory cells. Each word line is connected to a row of memory cells, and each bit line is connected to a column of memory cells. The control circuitry includes word line select circuitry and bit line select circuitry to select a number of memory cells for writing and reading operations.