Design a Collector with More Reliability against Defects during Manufacturing in Nanometer Technology, QCA ()
Abstract
Nowadays Quantum Cellular Automata (QCA)
as the leading technology in design of microelectronic systems has been raised.
With respect to high velocity and density in low power and also simple concepts,
this technology is a viable alternative to CMOS technology. In collector design, the primary component of
each processor is very important. Due to the small elements in this technology,
failure rate in manufacturing process technology is very high. In the other hand,
the simulation shows that the intersection point of two wires is one of the critical
points in QCA circuits. This means that defects in the manufacturing process around these
points can cause malfunction in the circuit performance. In this paper, a collector in cross sections of wire in
his new method used higher reliability against defects during manufacturing has been developed. QCA Designer software
is used to simulate the case study system.
1. Introduction
Quantum cellular automata (QCA) is a nano-scale technologies due to its speed and high density, low power, and simplicity, its alternative technology CMOS is considered. About 100 thousand times the risk of failure in this technology than the manufacturing technology in CMOS has been reported [1]. Therefore, when designing circuits, QCA fault tolerance circuits should be designed with special attention to the process of making this technology encounter with a lower failure rate. In the contrary of CMOS technology that information transferred from a point to another point by electrical current, in QCA technology information is transferred base on coulomb interactions.
The collector is fundamental and primary component of a microprocessor. Implementation of this sector as one of the most important part, in any technology is introduced. Due to electrostatic aspects of the technology, layout of circuits and pass the two different wires together is very important in design process. Simulations shows that the intersection points of two wires are one of the critical points in QCA circuits. This means that the incidence of defects in the manufacturing process around these parts can cause malfunction in the circuit performance.
In this paper, Layout of a new collector is presented. This new method has been used in design of intersection points for the circuit that can be brought more reliability. The following sections of this paper are:
Section 2, overview of performance QCA; Section 3, an overview of manufacturing defects in QCA; Section 4, the proposed adder structure; Section 5, layout design of proposed adder; Section 6, reduce consumption levels proposed adder; and Section 7 is conclusion.
2. QCA Performance
QCA device is a collection of cells QCA [2]. A quantum cell QCA, consist of four quantum dots that are coupled to the capacitive and tunnel barrier [3]. Two additional electrons within cells that can move freely between the four points but the phenomenon of tunneling into and out of cell is not possible. Therefore two further electrons enmeshed on cell and situated against together in each corner of cell and it caused to −1 and 1 polarization on the cell.
Figure 1(a), a symbolic display of a cell in two different modes polarized which is equivalent to a binary zero and one shows. In the pattern of the technology, rather