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Science

The Half Adder: Synopsis of the Logic Circuit Component

half adderIntensive research to meet the recent demands in reduced power computing and operation on a smaller scale has led to reducing computing components from Silicon. Electronic devices data processing components viz logic circuit and transistors which are used via voltage control have seen remarkable breakthroughs in recent times. One of the smallest make-ups of the Logic Circuit is the Half Adder. The Half-Adder’s reduction in size had been an issue that had been on the works for sometime now. However, there has been a landmark stride made in this regards.

Latest Advances

Researchers from the UK and Asia recently designed a five transistors Half-adder logic circuit. Applied Physics Letters had their paper published in its recent issue. A Professor of Physics in South Korea, Jung-Bum Choi, posited the innovative breakthrough. Drawing from his words, he said that the Half Adder which is one-electron based was made for the Multi-Valued (MV) components with emphasis on the Single Electron Transistor (SET).

He further explained that the Half Adders make up a Logic Circuit and the Half-Adder has two key roles it plays, which are its flexibility and its Multi-Value. This recent breakthrough in the fabrication of the Half Adder with a single electron makes for reduced power/large scale combinations and a reasonably high density in its functionality.

The Half-Adder in the Logic circuit is one of the smallest components used in arithmetic. It can generate two results by putting together two numbers with single digits. It carries and sums the digits and has the ability to add carried numbers in further calculations when multi-digits are involved in the process.

In the Conventional Half-Adder (CMOS) model, the Field-Effect Transistors (FETs) at the barest minimum would be 20. However, the recent works of these scientists produced a Half Adder with an amazingly low number of two Field-Effect Transistors (FETs) and three Single Electron Transistors (SETs). In their demonstrations of their research work; they also showed that by the simple change in the control gate of a Single Electron Transistor, the subtraction functionality in the Single Electron Half-Adder could be activated. When it is subtracting, the carries and sums become borrow and difference in its functionality.

A Further Look at the Cumulative Effects of the Half-Adder

Professor Jung-Bum Choi, A Professor of Physics in South Korea, further reiterated that two symmetrical side-gates with a solid Single Electron Transistor Platform is part of the make up of the new Single Electron Half Adder. This modification in structure, shape and design has made it possible for the use of just two Field-Effect Transistors (FETs) and three Single Electron Transistors (SETs).
This new design in the structure of the cell in comparison with the conventional CMOS design is quite phenomenal. The components that make up the new design are quite compact because previous models of the Half Adder needed at least 20 Field Effect Transistors. Another point to note is that the binary nature of the CMOS model which had only 0 and 1 had a lot of limitations in its functionality. The new Single-Electron Half-Adder in contrast has good flexibility and a good multi-value. This makes the density of integration quite effective.

One major challenge that has limited the functionality of the Half Adder is the implementation delay. This is due to the fact that the Coulomb oscillations should have three Single Electron Transistors (SETs) which possess phases that are identical. The previous processes of nanofabrication had high levels of complication which created challenges in getting these results just mentioned.
The Positive Traits of the Half Adder

Nano-electronics terabit level in the coming years would definitely experience positive, upbeat changes. The new logic cell with the single electron Half Adder has a smaller size and their power usage is very low. The Memory units and the Central Processing Units (CPU) in both Personal Computers and the Mobile System would definitely be seeing new applications in this regards.
Other Key Information

Work is still ongoing to make the Half Adder function at room temperature levels. Present ratings put it at a 10K operational temperature which is low but more work is still being done for further reduction.

Generally, it is pertinent to note that the One-electron Half Adder is currently the smallest component when it comes to Single Electron Transistors (SET) and the Multi-Value elements. With its positive contributions and qualities, it is definitely a step forward in the right direction.