CMOS stands for Complimentary Metal Oxide Semiconductor. CMOS technology is used to produce integrated circuits( IC) found in different types of electronic components such as microprocessors, batteries, microcontrollers, memory chips like RAM, ROM, EEPROM, and Application-Specific Integrated Circuits (ASICs)., digital cameras image sensors, RF circuits, highly integrated transceivers for different communication types, etc. This technology is currently one of the most popular technology in the computer chip design industry.
This is a type of MOSFET, metal oxide semiconductor field-effect transistor, fabrication process. This uses complementary and symmetrical pairs of p-type and n-types MOSFETs for logic functions. Each MOSFET includes two terminals namely source and drain and a gate that is insulated from the body of the transistor. When Imphal voltage is supplied between the gate and the body, electrons flow between the source and drain terminals.
By 2011 99% of IC chips are fabricated using this technology which includes digital, analog and mixed-signal ICs.
CMOS (Complementary Metal Oxide Semiconductor) Fabrication Technologies
There are four different processes in which a typical Complimentary Metal Oxide Semiconductor (CMOS) VLSI IC is manufactured, namely:-
Twin Tub Process
Silicon on Insulator (SOI) Process
Characteristics of CMOS device
These devices are high noise immune
They have a low static power consumption
These characteristics became the reason for most widely used technology to be implemented in VLSI chips as it allows CMOS to integrate a high density of logic functions on a chip.
Construction of the CMOS circuit
In this physical structure of MOS field-effect transistors, there is a metal gate electrode placed on top of an oxidizer insulator which again is on the top of a semiconductor metal such as aluminum or polysilicon.
CMOS logic has an advantage of 7times lesser power consumption than NMOS logic and BIPOLAR technology. Hence commercial Complimentary Metal Oxide Semiconductor (CMOS) products are built having up to billions of transistors of both CMOS and NMOS logic on a rectangular piece of silicon ranging between 10 and 400 mm².
The advantage of CMOS over NMOS logic is that both high to low and low to high output transitions are fast. A Complimentary Metal Oxide Semiconductor (CMOS) circuit has almost no static power dissipation that means power is only dissipated in case the circuit switches.
Uses of CMOS technology
Besides digital applications, this technology is used in analog applications such as operational amplifiers. Transmission gates used is analog multiplexer instead of signal relays. It is also used for RF circuits to microwave frequencies in mixed-signal applications.
Baseband processors, radio receivers in modern wireless networking devices and mobile phones use RF CMOS devices as this circuit helps to transmit and receive wireless signals. Also, it is used in satellite technologies such as GPS, Bluetooth, Wi-Fi, near field communication, mobile network suggests 3G and 4G, terrestrial broadcast and automotive radar applications.
Commercial RF Complimentary Metal Oxide Semiconductor (CMOS) products are used in wireless LAN networks GSM transfer syllabus for mobile networks and remote units in wireless sensor networks.
This technology is very beneficial for modern wireless communication one of the companies that commercialize technology was Infineon. During 2018 the company’s bulk RF CMOS switches sell over 1 million units annually.
These are known for their efficient use of electrical power as they do not require electric current except when they are charging from one state to another. this is the reason these have replaced previous designs like CCDs in camera sensors and are used in most modern processors.
Another name for CMOS
Complementary Metal Oxide Semiconductor (CMOS) is also referred to as Real-Time Clock (RTC), CMOS RAM, Non-Volatile RAM (NVRAM), Non-Volatile BIOS memory, or complementary-symmetry metal-oxide-semiconductor (COS-MOS).
What is CMOS Battery?
The Complementary Metal Oxide Semiconductor is usually powered by a coin-sized CR2032 cell battery, referred to as the CMOS battery. In most cases, CMOS batteries last the lifetime of a motherboard, sometimes up to 10 years and sometimes it needs to be replaced earlier, too. Incorrect or slow system date and time, and loss of BIOS settings are some of the major signs of a dead or dying CMOS battery in the computer device.
When a computer device is first started, options flashes on screen to boot into BIOS or CMOS. Opening the CMOS setup helps to change the settings it’s storing, like the date and time and how the different computer components are first started.
CMOS Settings in Computer
Complementary Metal Oxide Semiconductor (CMOS) is a physical part of the motherboard being a memory chip that accommodates setting configurations and is powered by the onboard battery. The CMOS reverts to the factory settings if the power of the battery is drained. Commonly the battery is removed to flashback CMOS setting if there is some configuration problem in the computer device. To enter into the CMOS settings press F1, F2, Dell or escape depending upon motherboard type.
CMOS menu setting contains hardware customization options success expansion port speed configuration, boot device order, power control on memory handling, etc offered by the motherboard, use a simple graphical interface and can be controlled by the keyboard.
But it is highly recommended to adjust the settings only if you are a pro-level user of the device because of improper setting adjustment scans in render computers unusable. Also, some advanced setting can lead to overheating of the system using extra power.
One of the most important roles of CMOS is, it is helpful in altering the device boot process.
Optical innovation is utilized in machine vision for robots, in optical character acknowledgment (OCR), in the preparation of satellite photos and in the upgrade of radar pictures, particularly for meteorology.CCD sensors have been mass delivered for a more extended timeframe, so they are progressively adult. They will, in general, have a higher caliber and more pixels.CMOS chips can be created on pretty much any standard silicon creation line, so they will, in general, be incredibly cheap contrasted with CCD sensors.
CCD sensors, as referenced above, make great, low-commotion pictures. CMOS sensors, generally, are increasingly vulnerable to clamor.
Since every pixel on a CMOS sensor has a few transistors situated by it, the light affectability of a CMOS chip will, in general, be lower. A significant number of the photons hitting the chip hit the transistors rather than the photodiode. CCDs utilize a procedure that devours heaps of intensity. CCDs expend as much as multiple times more force than a proportionate CMOS sensor. CMOS chips can be created on pretty much any standard silicon creation line, so they will, in general, be incredibly economical contrasted with CCD sensors.