Semiconductors – Yesterday and today
30 September 2010
The story of modern electronics is the story of the semiconductor. Rick Zarr looks back (and forward) at the influence of the semiconductor industry’s influence on society.
It was 1893 during the World’s Columbian Exposition in Chicago (in Illinois, USA – also known as the 1893 World’s Fair) that Westinghouse and Nikola Tesla introduced AC power, electric motors and incandescent light to the Victorian era population. People were extremely fascinated with this new form of energy – this fascination began a journey of technological revolution bringing our society to where it is today. If someone were to hand a modern cellular handset like a Droid or iPhone to someone in that time, they would have thought it was all done with magic not science. We have come a long way and in this article we’ll examine our trek over the last 30 years and look closely at the influence the semiconductor industry has had on our world.
Early days of semiconductors
I remember the summer of 1982 when it arrived in our lab. The news spread quickly around the office and everyone came to see what had been delivered… as it was unpacked on one of the lab benches we all took a breath in amazement – it was a 5.25 inch full height hard disk drive made by Control Data Corporation… the capacity was 5 megabytes! It weighed around 4.5 lbs, used 40 W of power, required a controller board full of integrated circuits and cost over $1000 (over $2000 today). We commented on the capacity and someone said, “How could anyone use all of that storage in a PC.” After all, most programs were 5 KB to 10 KB and most machines had 64KB of main memory!
Today that 5MB drive would not even hold a single MP3 encoded song. Hard drives have shrunk in size substantially and routinely hold well over 2 Terabytes or 400,000 times more information than that early device we had in our lab. Through a combination of new technologies in hard drive recording and optical tracking along with incredibly higher gate densities in ASICs, new drives are so small they can fit inside a match box. This and many other examples are possible due to the amazing evolution of the semiconductor industry.
Another good example is cellular telephony. Around the same time Motorola had just released the DynaTAC 8000x cellular phone. This was one of the first “hand-held” phones, but it was not a lightweight. It weighed around 2.5 lbs and occupied about 80 cubic inches – it also doubled as a club in case of attack. It was so heavy and bulky it was actually referred to as the “brick” phone. Today an iPhone 4G or Droid phone weighs less than 5 ounces and fits easily in the palm of your hand. The 1983 DynaTAC had a maximum capacity of 30 phone numbers… if you were to purchase a 32 GB iPhone 4G, the equivalent storage (without other functions) would be over 9.1 billion phone numbers – you could store every phone number on the planet… but these new marvels of technology are not simply a phone as their predecessors were. They are computers with the ability to shoot digital still pictures or video, find your location through GPS, play music, watch movies, play games, do research, send and receive email and other forms of communication and so much more, the list is truly endless on what is possible. And again, all of the support systems (base stations, satellites, back haul, Internet) would not be possible without the never ending march forward of semiconductor technology.
It is interesting to think about how much has changed in just the last 30 years.
Processors ran at megahertz speeds and packaging technology required large dual inline styles. Bus architectures were wide parallel designs: if engineers wanted to move more data they simply made the bus wider until clock skew and jitter would introduce errors. Today high speed designs serialise the data embedding the clock along with the data eliminating the skew issue.
Process technology has also improved by incredible leaps. In 1980 the state of the art digital CMOS process had gate geometries of 1500 nm (1.5 um). Through the improvement of wafer processing with higher purity silicon, improved mask building and lithography, the industry is now commercially producing CMOS processes with geometries below 45 nm.
That’s 34 times smaller than those early digital processes – this march of improvement was predicted by ‘Moore’s Law’ coined by Intel co-founder Gordon E. Moore. His modified law states that the transistor count on a single die will double every 18 months (his original projection in 1965 was every 12 months, later revised to 24 and now modified to every 18 months which is holding very true).
With all of those transistors, engineers could build systems on a single chip leading to an explosion of low cost consumer electronics and hand-held devices such as cellular phones, music players and game stations. Today we see a fusion of all of these things in a single hand-held device that is not only a communicator (via many channels; voice, email, blogs, etc.), but a complete information system that provides tremendous information. Automation systems created on this technology provides much of the food and clean water society needs, and many would die if the technology were to disappear.
The level of information available today would not be possible if it were not for the massively interconnected machine called the Internet. The amount of computing power has grown exponentially over the years and through the invention of packet switching has allowed hundreds of millions of computers to be interconnected. The future of this is obvious. A recent study by Cisco systems projected that by 2015 65% of the worlds mobile traffic will be video! It is not hard to imagine person-toperson video calls, but what is hard to imagine is the massive network that is required to provide that level of service. If not for higher levels of integration for digital systems, this vision would not be possible.
In the analogue world, simply providing an integrated power regulator was a major step during this early period. National Semiconductor pioneered the integrated low-dropout regulator in the early 1980s and has continued to integrate higher levels of power management into a single package such as the Simple Switcher Power Modules. Like National, other analogue vendors have also continued to highly integrate analogue systems. Analog Devices, ST and others have integrated complete micro machined accelerometers onto a single device providing hand-held devices and game controllers with the ability to detect motion with multiple axes. This has enabled better navigation systems as well as fun games such as the Wii.
The future of semiconductor technology
It is hard to gaze into a virtual crystal ball and predict the future of technology and semiconductors (or anything else). What can be done with some certainty is to extrapolate current technologies into the near future and imagine what could be done. A good example of this is solid state lighting. LED lights have been around for some years with the invention of the blue and white high brightness LEDs. However, the implementation complexity and cost have limited their use to specialty applications such as jumbo displays, landscape and art lighting and colour washes. There have been recent breakthroughs by companies such as Lumius Devices using quantum well confinement to enhance photon generation and photonic crystals (tiny waveguides etched into the LED die) to allow more photons to radiate dramatically increasing the efficacy of these LEDs. At the same time, the semiconductor industry has created highly integrated off-line LED drivers for general purpose lighting such as the LM3445 that provide bulb manufacturers with a way to make an Edison base replacement bulb at a reasonable cost.
Another area of evolution is to smaller process nodes. It is thought that production of FET structures can continue down to roughly 15 nm with higher levels of integration by building 3D vertical channels (instead of lateral structures).
Beyond that, the next step may well be quantum dot transistors used to create cellular automata logic. No longer will a logic state be measured by the flow of electrons in a gate, but rather by the position of the electrons. States would change so rapidly that the equivalent clock speeds would exceed 40,000 GHz! For the near term, power and efficiency will still be an issue so analogue vendors are looking at more elaborate processes such as SiGe and GaN for higher speeds and higher power capability respectively. The next 30 years will be exciting to say the least and only our imaginations will limit what is possible.
RICK ZARR is a technologist at National Semiconductor
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