#390 – An Interview with Sam Zeloof

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• Welcome Sam Zeloof!
• Sam is graduating high school soon, he’s currently finishing up his senior year.
• Sam started the process of making semiconductors in his garage 1.5 years ago
  • 0h 1m 15s
• Sam was inspired by Jeri Ellsworth’s videos
  • 0h 2m 45s
• He’ll be attending Carnegie Mellon University in the fall.
  • 0h 8m 7s
• Book: Microchip Fabrication by Peter Van Zant
  • 0h 10m 23s
• Chemicals are hardest to get
  • 0h 12m 21s
• HF in contained in Whink Rust Cleaner
  • 0h 12m 40s
• Stump remover
  • 0h 12m 54s
• Boric Acid is in roach killer
  • 0h 12m 59s
• Sam gives a tour of his lab 
  • 0h 14m 10s
• Recently finished version of a Dual PMOS differential amplifier!
  • 0h 15m 49s
• UPDATE: Sam has published about his recently completed IC
• Added SEM
  • 0h 16m 3s
• Wasn’t an option to buy a vapor deposition machine, needed to build
  • 0h 17m 43s
• It was PVD, not CVD
  • 0h 18m 9s
• Sputtering aluminum
  • 0h 18m 59s
• Mean Free Path
  • 0h 20m 26s
• Follow along with the slides Sam prepared for a recent showcase of his work in Newark at the Trenton computer fest
  • 0h 20m 52s
• Start with wafer, buy off eBay
  • 0h 24m 48s
• Check resistivity
  • 0h 25m 10s
• Might be obvious, but Sam is not in a clean room
  • 0h 27m 13s
• Both Sam and Chris have worked in a Class 100 clean room
  • 0h 28m 10s
• UDC internship working on organic LED processes
  • 0h 28m 18s
• Oxidizing layer
  • 0h 29m 43s
• Photolithography
  • 0h 30m 9s
• Silicon gate vs metal gate
  • 0h 31m 36s
• Self aligned gate
  • 0h 32m 14s
• 4 mask set
  • 0h 33m 3s
• What is doping?
  • 0h 33m 42s
• Electrons and holes. Talking about holes makes understanding organic semiconductors easier.
  • 0h 35m 37s
• Dopants are ppm and ppb
  • 0h 37m 55s
• Phosphine and diborane
  • 0h 38m 49s
• Adding chemicals and then diffusing
  • 0h 41m 14s
• Hardest piece to find is the furnace
  • 0h 41m 26s
• HF acid
  • 0h 46m 26s
• HF etching of photoresist/oxide
  • 0h 49m 26s
• Adhesion promoter HMDS
  • 0h 50m 13s
• Spinning on the dopants
  • 0h 53m 40s
• Spin coating allows uniform application
  • 0h 54m 0s
• Migration of dopants down into the lattice
  • 0h 54m 52s
• Get rid of thick oxide
  • 0h 57m 12s
• Grow gate oxide
  • 0h 57m 25s
• Field oxide is 5000-10000A
  • 0h 57m 49s
• Gate oxide is 500 A
  • 0h 58m 11s
• Alignment on wafers
  • 0h 59m 43s
• Doing photolithography with a projector
  • 1h 0m 49s
• Mike Harrison talking about projectors
  • 1h 2m 26s
• EUV 13nm
  • 1h 2m 39s
• Double Patterning
  • 1h 3m 20s
• Scored corner and do y = mx + b
  • 1h 6m 30s
• Grateful dead bears
  • 1h 8m 25s
• Zeloof Semiconductor
  • 1h 9m 57s
• Thinner layers you dilute etchant
  • 1h 10m 45s
• Curve tracer
  • 1h 12m 1s
• Polished surface is tough for probing
  • 1h 12m 48s
• Make a 4 pin pogo tester
  • 1h 13m 2s
• 3rd masking step (contact)
  • 1h 14m 28s
• Metalization
  • 1h 15m 30s
• Everything is shorted
  • 1h 15m 36s
• Need to expose the traces that are remaining
  • 1h 15m 42s
• How many transistors are you making?
  • 1h 16m 33s
• Dual differential amplifier
  • 1h 17m 40s
• With larger feature sizes if it looks good, i’ts going to work
  • 1h 18m 26s
• CMP
  • 1h 19m 35s
• Little Lisa slurry
  • 1h 19m 54s
• Silane and CVD isn’t an option
  • 1h 21m 6s
• Polysilicon enables more types/more intricate transistos
  • 1h 21m 35s
• Max output swing isn’t possible with metal gate
  • 1h 22m 17s
• Itsy Chipsy chip service
  • 1h 28m 1s
• Design tools – Magic VLSI
  • 1h 28m 41s
• Drawing block of transistors
  • 1h 29m 17s
• QFlow
  • 1h 29m 34s
• Going from Verilog to masks
  • 1h 30m 4s
• MOSIS
  • 1h 33m 36s
• Wirebonder in process
  • 1h 34m 25s
• Former guest Tony Long might have one?
  • 1h 34m 54s
• CMU has a new cleanroom and Sam will be allowed to work there as a freshman
  • 1h 36m 8s
• Find Sam on YouTube, Twitter and via email
  • 1h 37m 46s