HP has revealed another aspect of its crossbar switch technology that it hopes will replace transistors as the main off-on switch in semiconductors.
The idea involves greatly enhancing the demulitplexer, a device that allows cell phones to communicate through different channels when the primary channel is down, into chips made of crossbar switches. These chips will also contain approximately 50 percent more interconnects -- the microscopic wires that connect the millions (and soon billions) of transistors on a chip -- than today's processors.
By adopting these two ideas, HP hopes, chip designers will be able to skirt the major problem of defect density facing semiconductor manufacturers in the nanotechnology era and radically reduce costs. Simply put, increasing the number of transistors on a chip increases the odds that the chip will have fatal defects. Meanwhile, the shrinking size of these transistors means that it will be increasingly expensive and difficult to ferret out these defects.
"By using a crossbar architecture and adding 50 percent more wires as an 'insurance policy,' we believe it will be possible to fabricate nano-electronic circuits with nearly perfect yields even though the probability of broken components will be high," Stan Williams, HP senior fellow and director, Quantum Science Research at HP Labs, said in a statement.
Inserting redundant circuits is a common practice in semiconductor manufacturing. The many problems Transmeta had when it came out with its 5800 Crusoe chip in 2001 were due to a lack of redundancy, many sources at the time said.
HP, though, is substantially expanding on the concept and tailoring it for its crossbar structures. The regular, predictable structure of crossbars makes them fairly well suited for demultiplexing, HP said.
Many of the mathematical ideas behind crossbars derive from theories devised by Claude Shannon in the 1950s. More details will be provided in an article published by the Institute of Physics.
The race to find replacements or enhancements for transistors has accelerated in the past few years because of the increasing difficulty of following Moore's Law, which states that engineers can double the number of transistors on a chip every two years. Williams said in a recent interview that the 40 years of steadily increasing computing performance by adding more transistors to chips is the greatest technological achievement of civilisation.
HP is trying to get chipmakers to adopt crossbar latches for the 32-nanometre generation of chips, which are due toward the end of the decade. HP will charge royalties under license to semiconductor makers who adopt the design.
