SCEN103 Class 28

Building a Transistor

• Pentium Pro, recently available from Intel, has 5.5 million transistors.
• About 10 years ago, the 386 microprocessor was introduced;
  it had 275,000 tranistors on a chip of silicon about 1cm x 1cm.
  
• How can so many transistors be put on such a small amount of silicon?
• The following table was compiled from the ChipList, by Aad Offerman
  

  Date	Intel	Transistors	Technology
  	CPU	(x1000)
  1978	8086	29	2.0 micron
  1982	80286	134	HMOS
  10/85	80386	275	0.8 micron CMOS
  04/89	80486	1200
  05/93	Pentium (P5)	3100	0.8 micron biCMOS
  11/95	Pentium Pro (P6)	5500	0.6 micron biCMOS
  1997?	P7	14000	0.35 micron?

• Graph of the data above.

Lithography

• Schematic of npn transistor (viewgraph)
• Schematic of diffusion doping procedure (viewgraph)
• Slide show of doping steps for fabricating feature on silicon

• What limits the number of transistors on an integrated circuit?
• Why put more transistors on an integrated circuit?
• Why not make just make the integrated circuits bigger to get more transistors on them?
• Slide show on Integrated Circuit Yield

Online Resources