What are they?
- The natural world is analog while computing is digital.
- Computers perceive the natural world through sensorchips whose output is analog.
- The analog output is converted into the language of computers through a digitizer chip or an analog to digital converter (ADC).
- Foundries mass-produce these chips. Ideally, these chips should be identical but manufacturing variations produce tiny offsets which are revealed upon testing. This renders a large fraction of chips useless.
- The tiny offset may be stored in memory once and applied to the output afterward to make each imperfect chip usable for various purposes.
Why in News?
- IIT Bombay researchers have developed a “memory technology” that can, in principle, revolutionise Indian industry and the many applications that need semiconductor chips.
Applications of Memory Chips
- Defence sector, automobiles and future aspirations in cell phone manufacturing.
- Hard disks, flash memory, etc, are other areas using memory technology.
- There is also another form of memory called the one-time programmable memory (OTP) where the memory is written once, stored for a lifetime, and retrieved and used many times.
- This finds varied uses, one of which is in correcting faulty chips that have been mass produced for specific applications.
How does it work?
- Example: Due to a manufacturing defect, a chip may read 100 degree Celsius as 101 degree Celsius. This “offset” of 1 degree may be corrected by storing the error correction parameter in the OTP memory. This is done uniquely for each chip and once stored, the memory corrects the chip’s output for its lifetime.
- OTP memories are also used for other purposes, mainly three: chip identity, secure information storage and chip calibration for error correction.
- To store the correction value, the researchers used memory cells, each of which would store one “bit” (that is a value of zero or one).
- Each of the memory cells consist of ultrathin silicon dioxide layers. This is deposited uniformly over a silicon wafer to form millions of nanoscale capacitors.
- The OTP memory remembers either the “0” state or “1” state through its lifetime.
- A large fraction of manufactured chips may previously need to be discarded for faults that can be corrected using this technology.
- This technology is the first indigenous semiconductor memory technology adoption to manufacturing at 180-nanometre nodes.
- Thus, this is a major national milestone for semiconductor innovation.
To read about semiconductor chips- https://officerspulse.com/chip-shortage/