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A compound semiconductor is a semiconductor compound composed of chemical elements of at least two different species. These semiconductors form for example in periodic table groups 13–15 (old groups III–V), for example of elements from the Boron group (old group III, boron, aluminium, gallium, indium) and from group 15 (old group V, nitrogen, phosphorus, arsenic, antimony, bismuth).
The various metal layers are interconnected by etching holes (called "vias") in the insulating material and then depositing tungsten in them with a CVD technique using tungsten hexafluoride; this approach can still be (and often is) used in the fabrication of many memory chips such as dynamic random-access memory (DRAM), because the number of ...
While silicon is the prevalent material for wafers used in the electronics industry, other compound III-V or II-VI materials have also been employed. Gallium arsenide (GaAs), a III-V semiconductor produced via the Czochralski method, gallium nitride (GaN) and silicon carbide (SiC) are also common wafer materials, with GaN and sapphire being ...
China imposed export curbs last year on gallium and germanium, two metals used in computer chips and solar cells, to "safeguard national security."
The Biden administration later upped the ante and introduced export control measures in October 2022 that curbed the sale of advanced chips or chipmaking equipment to China without permission.
Finally, the package must permit interconnecting the chip to a PCB. [1] The materials of the package are either plastic (thermoset or thermoplastic), metal (commonly Kovar) or ceramic. A common plastic used for this is epoxy-cresol-novolak (ECN). [2] All three material types offer usable mechanical strength, moisture and heat resistance.
The top-most layers of a chip have the thickest and widest and most widely separated metal layers, which make the wires on those layers have the least resistance and smallest RC time constant, so they are used for power and clock distribution networks. The bottom-most metal layers of the chip, closest to the transistors, have thin, narrow ...
Now in the Smithsonian Chip collection. In 1973 Dr. John McGinness produced the first device incorporating an organic semiconductor. This occurred roughly eight years before the next such device was created. The "melanin (polyacetylenes) bistable switch" currently is part of the chips collection of the Smithsonian Institution. [9]