“In 1958, Jack Kilby built the first integrated circuit flip-flop with two transistors at Texas Instruments. In 2008, Intel’s Itanium microprocessor contained more than 2 billion transistors and a 16 Gb Flash memory contained more than 4 billion transistors. This corresponds to a compound annual growth rate of 53% over 50 years. No other technology in history has sustained such a high growth rate lasting for so long.”
-Principles of CMOS VLSI Design – A Systems Perspective by Neil Weste & Kamran Eshragian
Every electronics engineer knows about the Moore’s Law. We get to know about it from our professors, our books and all sorts of sources. It is one of the most important observations ever made and it deserves the attention. However, what makes me curious is that, for how long it is going to be valid. I mean, it has been more than 50 years since the inception of integrated circuits built using transistors. The number of transistors in the microprocessors these days are more than the number of seconds we live (based on average life expectancy). This makes me think; aren’t we moving towards a time where Moore’s law will cease to exist? There must be a limit, right? The foreseeable future for which the law was predicted can’t be infinite!
To ponder on this further and how will this impact the future of Microprocessors, let me answer the What, How and Why of Moore’s law in regards to Microprocessors.
What: The number of transistors getting doubled in a microprocessor every 2 years.
How: The size of the transistor keeps on reducing.
Why: To make the microprocessor faster (by increasing the clock frequency).
Answering and understanding the What, How and Why, I am in a better state of mind to comment on the limiting future of the Moore’s Law and it’s impact on the Microprocessors. For the Moore’s law to continue, the size of the transistor should continue to reduce at the similar pace as now. The possibility of reduction depends upon:-
- The technological ease of reducing the size.
- The ultimate limit till which the size can be reduced.
As the trend suggests the technological ease of reducing the size is getting tougher, hence the slow speed in reduction of size since 2007.
Also the maximum limit till which the size of the transistor can be reduced is the size of an electron (that is 0.0000028 nm). However, there is still a lot of scope before the minimum size is reached.
The importance and the ultimate aim of Moore’s law are to improve the computing capacity, speed and memory of a microprocessor.
This aim was being fulfilled by increasing the number of transistors leading to an increase in the clock frequency.
However, increasing the number of transistors also creates a problem of high power dissipation. Also, increasing the number of transistors by reducing the size of a transistor is becoming a harder job as seen above.
So, considering both these factors, it is quite evident that we need other ways to achieve a higher speed and efficiency in the microprocessor. This can be done by implementing parallel operating in the microprocessor. “Multi-Core” is hence the thing of the future.
To summarize I would say that the future of transistors is approaching its limit, technological advancement may get the Moore’s law going for some time, but the progression is slowing down. The power consumption by the high number of transistors is also a cause of concern. Therefore, other ways to make the microprocessors faster and more efficient have to be thought of. “Multi-Core-Technology”, single electron devices, Nano technology have an important role to play in the future.
P.S.: This post is my reading assignment in my Intro to VLSI Course this semester.
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