I like a great comeback story of technological innovation, battle, failure, and redemption. The invention of the scanning capacitance microscope has all of that.
In 1981, RCA filed a patent for the SCM on behalf of firm researcher James R. Matey. The microscope was an unintentional by-product of the VideoDisc know-how the corporate had been struggling to deliver to market because the mid-Sixties. RCA anticipated the VideoDisc to seize half of the house video market, however as an alternative it misplaced out in a giant solution to VHS.
RCA’s James. R. Matey invented the scanning capacitance microscope, which used sensors cannibalized from the corporate’s VideoDisc gamers. Hagley Museum and Library
Regardless of the VideoDisc’s struggles, the underlying know-how held a gem: The exquisitely delicate capacitance sensors used within the VideoDisc gamers had been able to measuring capacitance variations on the size of attofarads (1 × 10-18 farad).
However earlier than engineers and scientists might belief Matey’s concept, they needed an impartial analysis to verify the accuracy of the brand new microscope. Researchers on the Nationwide Institute of Requirements and Know-how obliged. Beginning within the early Nineties, they too cannibalized capacitance sensors from outdated VideoDisc gamers and custom-built a sequence of SCMs, such because the one pictured at high. After NIST’s validation, microscope producers commercialized the SCM, chipmakers adopted them to check built-in circuits, thus opening the door to the subsequent era of semiconductors.
Why the RCA VideoDisc Failed
However no story concerning the scanning capacitance microscope’s triumph could be full with out some dialogue of the VideoDisc’s failure. In concept, it ought to have thrived: It was a totally researched product that anticipated an necessary client market. Its playback constancy was superior to over-the-air programming and to magnetic tape. And but it bombed. Why?
The VideoDisc effort had begun within the early Sixties, when RCA requested itself, “What comes after coloration TV? What would be the subsequent main client electronics system?” The corporate determined that the reply was some kind of system to play prerecorded motion pictures and TV reveals by your tv. RCA was removed from alone in pursuing this concept. The entire dwelling video programs underneath improvement included a storage medium—movie, magnetic tape, nonmagnetic tape, and vinyl discs of varied measurement and composition—and a tool to play again the audio and video in excessive decision. Along with magnetic strategies, data may very well be saved utilizing electromechanical, photographic, electron-beam, or optical applied sciences.
RCA VideoDiscs had been simply broken by mud and fingerprints, so that they had been loaded into the SelectaVision participant inside plastic sleeves.Hagley Museum and Library
By 1964, RCA had settled on VideoDiscs. Like a file album (which the corporate had pioneered), a VideoDisc was a grooved vinyl platter that makes use of a stylus for playback. Not like a file, the VideoDisc carried each audio and video, at a a lot larger density, and the stylus was electrical as an alternative of mechanical. (The VideoDisc is usually confused with the LaserDisc, a house video know-how of that period that used an optical laser.)
RCA known as its discs Capacitance Digital Discs. The VideoDisc participant spun the 30-centimeter disc at a continuing 450 rpm. A metallic stylus traced the depressions and bumps within the disc’s groove by registering variations in capacitance, just like the best way that bringing your finger into contact with a touchscreen causes a detectable change within the display screen’s capacitance at that time. Stable-state circuitry unscrambled the frequency-modulated video sign encoded within the capacitance variations. These variations had been on the order of femtofarads, and the video sign ran at about 910 megahertz. To get a transparent image, the VideoDisc system required very delicate capacitance sensors to detect these tiny variations at excessive frequency.
Sadly, commercialization took for much longer than anticipated. In 1972, RCA introduced that its VideoDisc would debut the next yr, however it didn’t materialize. An article in Common Science in February 1977 anticipated regional gross sales by the top of that yr. However it wasn’t till March 1981 that the RCA SelectaVision system lastly hit the market. Regardless of heavy promotion, it bought poorly and was pulled from the cabinets in 1984. Ultimately, RCA sank about US $500 million over 20 years to develop the VideoDisc, and it was a complete flop.
How Videotape Vanquished the VideoDisc
What went unsuitable? In a phrase: videotape. Magnetic tape, which RCA had rejected, turned out to have larger client enchantment. Launched in 1976, VHS tapes had been cheaper, had extra titles obtainable for buy or hire, and, importantly, allowed house owners to file their very own packages.
Maybe if the VideoDisc had launched in 1973, it may need had an opportunity. However the know-how had different issues. Fingerprints, mud, and scratches torpedoed early designs that envisioned customers eradicating the discs from sleeves as casually as file albums; as an alternative, the ultimate model stored the discs encased in a plastic shell that was then inserted into the participant.
RCA spent 20 years creating its dwelling video system, however ultimately the SelectaVision misplaced out to VHS and VCRs. Hagley Museum and Library
One other downside was working time. In 1977, VideoDiscs might maintain solely about half-hour of fabric per aspect. That rose to an hour per aspect by the point of product launch, however that also meant that any film over 120 minutes must be unfold over a number of discs. The primary VHS tapes might maintain 120 minutes of video (double that of its most important tape competitor, Betamax). And VHS stored extending that lead: By the Nineteen Eighties, VHS had lengthy play (4 hours) and prolonged play (six hours) variations, albeit with noticeable drops in decision high quality.
RCA forecasters additionally badly misinterpret the economics of VideoDisc gamers. Their 1977 value estimate for a VideoDisc participant was $500 (about $2,800 in at this time’s {dollars}). The primary VHS gamers had been way more costly, starting from $1,000 to $1,400, however by the mid-Nineteen Eighties, their value had dropped to $200 to $400. VHS tapes of main Hollywood movies value about $80—way more than VideoDiscs’ $10 to $18 price ticket—however solely diehard followers really paid the trendy equal of about $440 to purchase a film on videotape. For everybody else, the Hollywood studios licensed titles to third-party rental firms. Seemingly in a single day, impartial video outlets, supermarkets, and nationwide chains like Blockbuster had been renting motion pictures for a small price. For a quick interval, RCA VideoDiscs shared the cabinets with videotapes, however normally solely at impartial outlets and by no means with as many titles obtainable.
In the meantime, RCA struggled to promote its VideoDisc gamers. The corporate had forecast eventual annual gross sales of 5 to 6 million gamers; its first-year aim was a extra modest 200,000, and but it bought solely half that quantity. By 1984, RCA realized the VideoDisc would by no means come near 50 % market penetration, not to mention profitability, and pulled the plug.
Start of the Scanning Capacitance Microscope
Usually that may be the top of the story, one other failed enterprise in client electronics. However again when RCA scientists first started researching the VideoDisc, there have been no microscopes able to figuring out the tiny variations within the disc that encoded the audio/video sign. The bumps and depressions had been lower than a tenth the scale of the groove itself; even essentially the most superior microscopes of the day couldn’t detect options that small.
A manufacturing facility employee inspects an RCA VideoDisc, which encoded the audio and video indicators within the disc’s groove. Hagley Museum and Library
And so RCA’s James Matey developed and patented the scanning capacitance microscope (which he abbreviated SCaM, however others correctly shortened to SCM) as a quality-control instrument for manufacturing the VideoDiscs. 4 years after the primary patent, RCA filed a reissue patent with some corrections and enhancements. In a really readable paper within the March 1985 challenge of the Journal of Utilized Physics, Matey and fellow RCA researcher Joseph Blanc defined the brand new know-how. The SCM might detect variations in floor topography on the order of 0.3 nanometers over areas on the order of 0.5 sq. micrometers. RCA delayed publication of this paper till it had shuttered the VideoDisc operation, and so Matey and Blanc concluded their paper, “We’re at present within the strategy of adapting [the SCM] for related makes use of on different samples.” The brand new use turned out to be within the manufacturing of the subsequent era of semiconductors.
Semiconductor efficiency will depend on the distribution of deliberately launched impurities, known as dopants, which change the power of the fabric to conduct electrical energy. Within the early days of semiconductor manufacturing, producers used ion mass spectroscopy and a method known as spreading resistance to measure the dopant distribution in a single dimension.
By the late Nineteen Eighties, built-in circuits had turn into so small that the trade wanted a solution to measure the dopants in two dimensions. The SCM, used along with an atomic power microscope, match the invoice. When the conductive tip of the atomic power microscope made contact with a semiconductor floor, it created a small capacitance, on the order of attofarads to femtofarads, relying on the dopant focus. The SCM measured the modifications of the native capacitance and mapped the dopant distributions. However the know-how was nonetheless novel and never but commercially obtainable, so researchers at NIST took up the duty of testing it.
Within the early Nineties, Joseph Kopanski, Jay Marchiando, and David Berning started constructing a sequence of {custom} SCMs on the NIST Semiconductor Electronics Division. They did extra than simply reproduce Matey and Blanc’s outcomes. Additionally they supplied the trade with fashions and software program for extracting two-dimensional dopant distribution from the capacitance measurements.
NIST’s validation of the SCM led to the business manufacturing of the devices, which in flip led to the event of more-advanced semiconductors—an trade that’s orders of magnitude extra necessary to the worldwide economic system than a client product just like the VideoDisc would ever have been. It’s a traditional story of redemption within the historical past of know-how: Firstly of any new tech mission, nobody actually is aware of what the end result will probably be. Typically, you simply must preserve going, even by abject failure, and belief that one thing good will emerge on the opposite aspect.
A part of a continuing series taking a look at historic artifacts that embrace the boundless potential of know-how.
An abridged model of this text seems within the October 2025 print challenge as “RCA’s VideoDisc Gamble Paid Off in Chips.”
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