Evolution of CMOS technology in brief?

CMOS History:

1. Invention of vacuum tubes.

• Huge size
• Complexity was high
• Power consumption was also significantly high

2. In 1947, William Shockley, John Baden, and Watter Brattain of Bell Labs invented the first point contact Germanium transistor.
3. In 1950, William Shockley developed the first BJT (Bipolar Junction Transistor).
4. Compared to vacuum tubes, transistors were:

• Smaller in size
• Reliable
• Power efficient

5. In 1958, Jack Kilby built the first IC consisting of two BJT’s connected on a single piece of Silicon which led to the dawn of “Silicon Age”.
6. Major drawbacks of BJT:

• More static power dissipation
• i.e. power is drawn even when the circuit is not switching
• This limit the maximum number of transistor that can be integrated into a single chip

7. In 1963, Frank Wanlass and C.T.Sah unveiled the first logic gate in which n-channel and p-channel transistors were used (now known as CMOS technology).
8. Early IC’s used NMOS technology because they were:

• Fairly simple
• Less expensive
• More devices could be packed into single a silicon chip

9. In 1971, Intel announced their first microprocessor.
10. During the 1980’s as thousands of transistors were integrated into a single chip, static power dissipation again became a serious issue and hence CMOS technology replaced NMOS and BJT technology due to its:

• Low power consumption/dissipation
• Less area
• Reliable performance
• High operating speed
• Scalable
• Manufacturability (Fabricated with fewer defects)
• Better performance-to-cost ratio (i.e. low cost per chip)
• Improved packaging density

In the upcoming posts, we will discuss each of these technologies in detail.