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Self Assembly
 (a) Step 1: Polymer molecules are made to self assemble into perfect hexagonal arrangements. The sizes of the arrangement are set by the size of the polymer molecules. The dark circular areas are 20 nanometers in diameter and are spaced 40 nanometers apart.
(b) Step 2: IBM used the polymer material as a stencil to reproduce the nanoscale pattern in silicon dioxide, which is more rugged than the polymer and able to withstand higher temperatures. At this stage the polymer material is completely removed.
(c) Step 3: A combination of depositing silicon material and etching leaves silicon nanocrystals embedded within the 20 nanometer regions defined originally by the self assembled polymer.
(d) Dimensions of the hexagonal pattern of the initial polymer (dotted curve) are maintained throughout, as shown by the histogram of the final silicon nanocrystal dimensions (solid curve). The grey curve represents the dimensions of the hexagonal pattern at an intermediate process step. [ More picture options ] [ Get permission to re-use ]
Nanocrystal memory device
 Arrays of uniformly-sized 20 nanometer diameter silicon nanocrystals (patterned using self assembly) are embedded between the device gate and silicon substrate. The device operates as a memory by storing charge in the nanocrystals. [ More picture options ] [ Get permission to re-use ]  Silicon nanocrystal arrays are formed between the device polysilicon gate and silicon substrate, and are electrically-isolated by control- and program-oxides. The nanocrystal dimensions and positions in our device are defined using self assembly. [ More picture options ] [ Get permission to re-use ]  The self assembly process IBM has used to construct our nanocrystal memory devices relies on the natural property that most polymer materials do not mix well (a similar phenomenon to mixing oil and water). [ More picture options ] [ Get permission to re-use ]
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