recommendation report
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silicon vs. carbon nanotechnology
Recommendation Report
Angel [email protected]
Submitted: December 3, 2015
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Table of ContentsContentsIntroduction......................................................................................................................................1
Purpose........................................................................................................................................1
Current Standing with Silicon.........................................................................................................1
Understanding transistors............................................................................................................2
Silicon limitations........................................................................................................................2
What are carbon nanotubes?............................................................................................................2
How are carbon nanotubes made?...............................................................................................2
Arc Discharge..........................................................................................................................2
Chemical vapor pressure..........................................................................................................3
The benefits of carbon nanotubes................................................................................................3
Capabilities of carbon nanotubes.................................................................................................3
Electrical Properties.....................................................................................................................3
Carbon Nanotubes in Electronics....................................................................................................4
Problems with Carbon Nanotubes in electronics.........................................................................4
Misaligned Tubes.....................................................................................................................4
Conductor Tubes......................................................................................................................4
Comparison of Carbon Nanotubes with Silicon..........................................................................4
Cost of Carbon Nanotubes...........................................................................................................4
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How else can carbon nanotubes be implemented?......................................................................5
Recommendation.............................................................................................................................5
Intel..............................................................................................................................................5
References........................................................................................................................................6
List of Figures and Tables
Figure 1Moore's Law.......................................................................................................................1
Figure 2 Research on Carbon Nantubes..........................................................................................2
Figure 3 single walled carbon nanotube..........................................................................................3
Figure 4 Types of Carbon Nanotubes..............................................................................................3
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Recommendation Report: Silicon vs. Carbon Nanotechnology
IntroductionEvery year elicits numerous advancements in technology. The standard is always pushed
to the limit by the next technological innovation. New iterations of every kind of technology are released every year. Whether it is for consumers or huge manufacturing corporations such as Intel, advancements are made to make the previous technology obsolete. This type of advancement is being made with the materials used to make processing chips.
Purpose This report will analyze the differences in silicon and carbon nanotechnology.
I will explain and compare the limitations and benefits of each material. Then I will determine how feasible carbon nanotechnology is and if it should be implemented into today’s computer processors. If so, in what kind of costs are involved? Then I will recommend a material based on the contents of this report to the Intel Corporation to implement into their processors.
Current Standing with Silicon As Intel recognizes, silicon is used in all of modern electronic processors. For the last
few decades many advancements have been made with silicon chips. The general trend is to keep making individual transistors smaller and smaller in order to fit more of them in the same amount of space. This, in turn, equates to more processing power. Furthermore, creative layouts and architectures are simultaneously being constructed to help boost performance. Engineers found that the smaller the processors were the less electricity they used and the more powerful they were. This lead to Gordon Moore, co-founder of Intel, theorizing that the number of transistors on integrated circuitry within a specified area will double every year beginning since the invention of integrated circuitry. [9] This is Moore’s law, and it has held to be true since he first theorized it. In Figure 1, the number of transistors is graphed every year based off of the new processor that was developed by Intel. It shows that Moore’s law has indeed held true.
Figure 1Moore's Law [3]
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Understanding transistors Transistors are the fundamental building block to processors. They operate in two ways,
as a switch and as an amplifier. The fundamental bases of how computers operate is through “off “and “on” signals. So transistors allow computers to operate the most common way possible which is by following “off” and “on” instructions. They then work as an amplifier to increase current in specific areas which allows more control within the circuitry. Thus it is then evident that the more transistors that are present, the more capable the processor is.
Silicon limitationsThese transistors are made of Silicon. Silicon, just as every other element, has its
capabilities and its certain limitations. The rate of advancements with this technology are decreasing. Moore’s law will soon prove to fail. The problem is that the smaller and smaller processors that are constructed are harder to manufacture and the sustainability of the element itself begins to suffer.[10] These transistors can only be put so close to each other before they cause interference among the other transistors in the circuitry. The electromagnetic fields of each transistor interferes and affects the current travelling within each surrounding transistor. This opens the doors to carbon nanotechnology, which has been exponentially researched all around
the world as evident in Figure 2.
Figure 2 Research on Carbon Nanotubes [10]
What are carbon nanotubes?
Carbon nanotubes are made of carbon atoms connected together through covalent bonds in hexagon formation. This is called graphene. This structure has the thickness of a single atom. Their length to
diameter ratio is 132 million to one respectively. They are the largest nanotubes to be discovered since 1991.
How are carbon nanotubes made?Arc Discharge
This method was one of the first used to create carbon nanotubes. The basic concept of it has been applied to many applications. It involves a vacuum sealed chamber with two conductor poles on opposite ends made of graphene, which is a carbon structure. A current is then sent through one end and jumps to the other pole. This jump is called an arc, and in the process of this arc, carbon nanotubes are created. This is because when the arc of current reaches the other pole, the end of the pole is burned do to current. The current causes the burned off graphene to rearrange into a carbon nanotubes. This process in turn leaves carbon nanotubes littered all over the chamber. This process produces all structures of carbon nanotubes, which will be discussed shortly.
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Chemical vapor pressureThis method is the most popular way to produce carbon nanotubes. This process involves
the thermal decomposition of a hydrocarbon vapor while in the presence of a metal catalyst which is used to construct the carbon nanotubes. In other terms, a carbon gas is first evaporated and heated to a really high temperature. Then this gas is led to a chamber where atoms of metal are laid out. The carbon in the vapor are attracted to the metal and build up around the metal atom. For instance, imagine that the metal atom is the bottom of a regular cup. When the carbon atoms approach it, they build up the walls of the cup. This then creates carbon nanotubes. The benefit to this method is that the diameter of the tubes can be dictated by the size of the metal atom that is used. [15]
The benefits of carbon nanotubesThe obvious benefits of carbon nanotubes is that they can be significantly smaller than
silicon structures. However, they also contain many other important attributes. The very structure of the nanotubes helps create the great electrical properties they possess. The tube shape allows electrons to flow along the tube making this a one dimensional conductor. Furthermore, nanotubes possess great strength and great flexibility. This opens the possibilities for many uses of the technology such as durable and bendable electronics that can withstand great amount of force. Another benefit is that they are light weight due to their single atom structure and hollow tube. They also have high thermal conductivity, predicted to have conductivity several times that of aluminum.
Figure 3 single walled carbon nanotube [1]
Capabilities of carbon nanotubesThe size of carbon nanotubes allows engineers to fit
more of them in an area than can silicon transistors in the same area.[10] In IBM’s new carbon nanotube chip, they were able to fit a billion nanotubes in every square centimeter. The magnification in Figure 3 gives us a glimpse of how small these tubes actually are. Carbon nanotubes are
also able to work in cooperation with silicon structures. [12] The difficulties lie in manipulating the nanotubes in order to create a chip made solely from nanotubes without silicon which will be discussed shortly.
Electrical PropertiesThese properties depend on the exact structure of the nanotube. There are three variations
of the nanotube, the armchair, zigzag and the chiral shown in Figure 4. Each structure places the atoms in different positions in relationship with each other which cause their electrical properties to vary. The armchair variant shares electrical properties with metals. The next two structures share properties of a semiconductor. This means that they only conduct current when energy in the form of light or electrical field hits them rather having current directly applied to them. These
latter two are most important in computer chip design while the armchair is ideal for replacing copper in wire. [6]
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Figure 4 Types of Carbon Nanotubes [5]
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Carbon Nanotubes in ElectronicsProblems with Carbon Nanotubes in electronicsMisaligned Tubes
In electronics, it is imperative that all parts are lined up perfectly on such a small scale. The slightest disorientation will cause a short circuit with the surrounding nanotubes. [8] A short circuit is simply when the current goes back to its source without being used. The found a solution to solve this problem. A series of computer algorithms can detect were those short circuits are because of their behavior and can then evaporate them by sending excessive current through the affected tubes. [2]
Conductor TubesAs previously discussed. Different structures of carbon nanotubes leads to different
properties. It is very difficult to eliminate all of one kind of tube in the manufacturing process. So researchers have found a solution that easily solves this problem. Since semiconductor tubes can be turned off and conductor tubes only let electricity flow. The solution is to turn off the semiconductor tubes and overload the conductor tubes with electricity until they literally evaporate. This eliminates any of the tubes that behaved like conductors and leaves only the semiconductor tubes. [2]
Comparison of Carbon Nanotubes with SiliconCarbon Nanotubes has proven thus far to seem superior. Their shape allows them to
transfer electricity at exponentially faster rates than Silicon is capable of. This allows computers to perform task faster and leads to less heat due to more efficient transfer of energy. Silicon will always have to go through extensive purification processes that will keep its cost constant despite the abundance of this element. Carbon nanotubes on the other hand, are being progressively manufactured by cost and product efficient means. [14]Thus, more tubes are being produced for a cheaper price. Also, the various methods to create carbon nanotubes leaves extensive space for improvement as far as manufacturing goes. Silicon is limited by the attributes of silicon itself, there is very little potential left to decrease the size of silicon transistors. Carbon nanotubes are already smaller in size than silicon with far greater electrical properties.
Cost of Carbon NanotubesThe price of carbon nanotubes has significantly decreased over the recent decades. From
thousands of dollars in its early stages a couple decades age. Advancements in the manufacturing process have allowed the price of carbon nanotubes to continuously decrease. Carbon nanotubes can currently be purchased for as low as three U.S. dollars. While the average cost lies around thirty U.S. dollars. [4]Silicon is still cheaper by comparable masses; however, due to the size and weight of carbon nanotubes being less, the quantity of nanotubes is far greater than the quantity of silicon. So the major
How else can carbon nanotubes be implemented?Carbon nanotubes have many other potentially beneficial applications that can be
achieved with continuing research. Many companies, such as Intel can greatly benefit from diversifying their company scope. Carbon nanotubes provide the ideal opportunity to do so, due
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to their excellent properties that can be utilized in many applications. Furthermore, since carbon nanotubes would be a main aspect of the company, working on other applications of them would not be a risky venture for the company. For example, carbon nanotubes can be used to create new x –ray machines. The traditional x ray machine relies on a filament to emit electrons when heated. [13] The new machine will possess an array of nanotubes that, due to the properties of nanotubes, will emit a substantially more amount of electrons which will allow the machine to take pictures from various angles. These nanotubes can also be used to replace the expensive fuel cells that power hydrogen cars. These fuel cells contain platinum which is an expensive and limited resource. Catalyst made from carbon nanotubes will provide smaller and more efficient fuel cells. Another application of carbon nanotubes is that they can be used to amplify sound; which equates to loud, small speakers. Carbon nanotubes properties can be beneficial to many more application, which will only open more doors for Intel.
RecommendationAfter analyzing the differences in silicon and carbon nanotubes, it is apparent where the
future is heading. Carbon nanotubes have so many possible uses and as soon as they become tamable, they will be used in many different fields. These nanotubes are the most promising way to advance technology as a whole. They possess the ability to reserve natural resources by being more power efficient and replacing other elements in different processes. These tubes are able to move electrons significantly faster than silicon. The price for carbon nanotubes continues to decline and will become the main focus of many more companies. Carbon nanotubes should be integrated into computer processing chips, because they consume less power, are more powerful, and will cost less in the long run. Silicon will fail Moore’s law and be replaced with Carbon nanotechnology.
IntelIntel should implement carbon nanotubes because they are on the high end spectrum for
computing chips. This implementation will allow them to maintain their standing in the semiconductor market. Furthermore, they will be able to make advances in the manufacturing process of carbon nanotubes that will continue cause the price to drop. Such advancements are not only beneficial to Intel, but technology in its entirety. Intel chips are found in the most demanding computational systems. They continue to push technology forward and carbon nanotubes is the ideal platform to continue doing so. Therefore, Intel should begin mass production of carbon nanotube processors.
References [1] “Carbon nanotubes,” www.ajayan.rice.edu, Accessed November 3, 2015. [2] “Carbon nanotube electronics,”www.physics.umd.edu, Accessed November 2, 2015.
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[3] Image, Moore’s Law, http://i-cdn.phonearena.com/images/articles/115059-thumb/000192-00.png
[4] “Global Market for carbon nanomaterials,”www.reuters.com, Accessed November 2 2015.[5] “Carbon nanotubes for faster computer processors,”www.azonano.com, Accessed
November 12, 2015.[6] “Scanning the properties of nanotubes,” www.understandingnano.com, Accessed
November 11, 2015.[7] Budnik. M., Raychowdhury. A., Roy. K, Power delivery for nanoscale processors with
single wall carbon nanotube interconnects, Nanotechnology, 2006. IEEE-Nano 2005 Sixth IEEE Conference on ISBN 1-4244-0077-5, 30 Oct 2006.
[8] L.Deferm, Goncal Badanes, Integration difficulties and limitations in sub-0.25 um CMOS and CMOS-based technologies, Microelectronics, 2000. Proceedings. 2000 22nd International Conference on ISBN 0-7803-5235-1, 6 Aug 2002.
[9] K. Zhang, Challenges and opportunities for circuit design in nano-scale CMOS technologies, ESSCIRC (ESSCIRC), 2012 Proceedings of the ISBN 978-1-4673-2212-6, 10 Nov 2012.
[10] B. Yu, M. Meyyappan, Nanotechnology: potential challenger to silicon CMOS? , Solid-State Device Research Conference, 2005. ESSDERC 2005. Proceedings of 35th European ISBN 0-7803-9203-5, 12 Dec 2005.
[11] E. Fazzion, O.L.H.M. Fonseca, J.A.M. Nacif, O. P. Vilela Neto, A.O. Fernandez, D.S. Silva, a quantum- dot cellular automata processor design, Title Integrated Circuits and Systems Design (SBCCI), 2014 27th Symposium on 22 Dec 2014.
[12] M.M. Shulaker, K. Saraswat, H. S. P. Wong, S. Miltra, Monolithic three-dimensional integration of carbon nanotube FETs with silicon CMOS, VLSI Technology (VLSI-Technology): Digest of Technical Papers, 2014 Symposium on ISBN 978-1-4799-3331-0 , 11 Sep 2014.
[13] “9 Ways carbon nanotubes just might rock the world,”www.discovermagazine.com. Accessed November 4, 2015.
[14] “Carbon nanotubes: pros and cons,” www.ezinearticles.com, Accessed November 2, 2015.[15] Mukul Kumar, Yoshinori Ando, Chemical Vapor Deposition of Carbon Nanotubes, Journal
of nanoscience and nanotechnology, Vol 10, 3739-3758, 2010.
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