60 questions · 31 almanac · 1 findings

Semiconductor Physics and Devices

The physics and engineering of transistors, diodes, and chips.

Almanac Two Gold Contacts, No Tube in Sight
  • What problem with vacuum tubes was Shockley's group at Bell Labs trying to solve using semiconductor materials?
  • How did the point-contact experiment on 23 December 1947 demonstrate amplification without a vacuum tube?
  • Why was Shockley not present for the crucial transistor experiment even though he led the research group?
Almanac A Sliver of Germanium Learns to Amplify
  • What did Bardeen and Brattain's germanium-and-gold-contact device do on 16 December 1947 that made it a transistor?
  • Why was Shockley's junction transistor design more practical than the original point-contact device?
  • How did replacing vacuum tubes with transistors change the physical size and power demands of computers?
  • In what sense is the transistor 'the most reproduced human artifact in history'?
Almanac A Whole Circuit on One Sliver
  • What problem in electronics was Jack Kilby trying to solve when he conceived of the integrated circuit?
  • What did Kilby's germanium oscillator demonstrate on 12 September 1958, and how large was the device?
  • What did Robert Noyce independently contribute at Fairchild Semiconductor that made integrated circuits manufacturable at scale?
  • How does eliminating hand-soldered connections between components improve a circuit's reliability?
Almanac A Switch That Barely Sips Power
  • What problem with the original bipolar junction transistor did Mohamed Atalla's silicon dioxide layer solve?
  • How does a MOSFET use voltage across an insulating oxide layer to switch on and off?
  • Why did the MOSFET's low power consumption make it the ideal building block for integrated circuits?
  • How many MOSFETs are manufactured annually today compared to when they were first demonstrated in 1959?
Almanac A Magic One, Coaxed Into Red Light
  • What semiconductor material did Nick Holonyak use to produce the first visible red LED?
  • Why was Holonyak's red LED a bigger breakthrough than earlier infrared LEDs?
  • What later innovation in blue LEDs made white LED lighting possible?
  • Why did LEDs remain an expensive laboratory curiosity for their first decade?
Almanac A Two-Page Plan for Shrinking Everything
  • What had Noyce and Moore already accomplished at Fairchild Semiconductor before founding Intel in 1968?
  • What does Moore's Law predict about transistor density, and why did it become a self-fulfilling prophecy?
  • How did the 4004 microprocessor, released in 1971, change the shape of the computing industry?
Almanac An Hour at a Whiteboard, Decades Ahead
  • How does a charge-coupled device store and read out image information?
  • What technologies today trace their imaging principles back to Boyle and Smith's 1969 sketch?
  • How long after inventing the CCD did Boyle and Smith receive the Nobel Prize?
Almanac A Whole Computer, Smaller Than a Fingernail
  • Why did Busicom's request for a twelve-chip calculator design lead Ted Hoff to propose a single programmable chip instead?
  • How many transistors did the Intel 4004 pack onto its chip, and how did that compare to earlier computing hardware?
  • Who designed the Intel 4004, and how long did it take to go from concept to production?
  • How did putting an entire CPU on one chip change what computing could be embedded into?
Almanac Twice a Laureate, Never a Third Try
  • What device did Bardeen co-invent at Bell Labs in 1947, and why was it significant?
  • Why is Bardeen the only person to have won the Nobel Prize in Physics twice?
Almanac A Circuit Small Enough for a Fingertip
  • How did Jack Kilby build the first integrated circuit while most of his colleagues were on holiday?
  • What is a semiconductor heterostructure and why does it help control electrons and photons?
Almanac Blue Light, Twenty Years Late
  • Why was blue light so much harder to produce from an LED than red or green?
  • How did Akasaki and Amano's crystal-growing method on sapphire substrates solve the gallium nitride problem?
  • Why does combining red, green, and blue LEDs into white light matter for global energy use?
  • What made Shuji Nakamura's route to blue LEDs different from the academic approach taken in Nagoya?
Almanac An Hour at a Blackboard, Then Every Camera
  • How does a charge-coupled device convert photons into a readable image, pixel by pixel?
  • What astronomical instruments and images relied on CCD technology, from the Hubble Deep Field onward?
  • Why did CCDs eventually become obsolete in consumer electronics despite thirty years as the best imaging technology?