# Solid State Fundamentals | Fundamental of Electronic Circuits Lesson 2

What exactly is solid-state technology?

Solid-state refers to electronic parts, devices, and systems made entirely of semiconductor materials like silicon, germanium, or gallium arsenide. The term “solid-state” was popular in the late 1950s and early 1960s during the transition from vacuum tube technology to diode and transistor technology.

Diodes and transistors, two of the most common types of solid-state devices, are heavily used in solid-state systems. Diodes and transistors come in various shapes and sizes, and they can perform multiple switching functions. Diodes can also function as rectifiers, converting currents from alternating current to direct current.

Transistors can also work as rectifiers, but unlike diodes, they can strengthen the signal. The transistor uses an outside power source to enhance the signal for amplification.

A diode with two terminals allows current to flow in one direction while blocking it in the other. Laser diodes, P-N junction diodes, and light-emitting diodes are typical examples (LEDs). A transistor has three terminals and can conduct current between resistance regions, making it more versatile than a diode. Bipolar junction transistors (BJTs) and field-effect transistors (FETs) are common examples.

## Solid State Fundamentals

Solid state fundamentals refer to the basic principles and concepts that underlie the behavior and properties of solid materials, particularly those with crystalline structures. These principles are based on the interaction of atoms and molecules within solids and the resulting electrical, optical, magnetic, and mechanical properties of these materials.

Some of the key concepts of solid state fundamentals include:

1. Crystal Structure: The regular arrangement of atoms or molecules in a solid is called the crystal structure. The properties of a solid are determined by the type of crystal structure it has.
2. Band Theory: The electronic properties of solids are governed by the arrangement of electrons in energy bands. The separation between these bands determines the conductivity of the material.
3. Defects in Crystals: Imperfections in the crystal structure of solids can have a significant impact on their physical properties. These defects can arise due to impurities, vacancies, or other factors.
4. Solid State Chemistry: The chemical behavior of solids is governed by the interaction between atoms and molecules within the crystal structure. Understanding these interactions is essential for developing new materials with desired properties.
5. Optical Properties: Solids can have unique optical properties, including the ability to absorb, reflect, and transmit light. These properties are determined by the electronic structure of the material.
6. Magnetic Properties: The behavior of magnetic materials is determined by the interaction between electrons and the magnetic field. These materials can have unique properties such as ferromagnetism, antiferromagnetism, or paramagnetism.

Overall, a thorough understanding of solid state fundamentals is critical for developing new materials with desired properties and for optimizing the performance of existing materials in various applications, including electronics, energy conversion, and sensing.

Integrated and solid-state circuits

Transistors and diodes are frequently combined with resistors, capacitors, and other components (IC) to make an integrated circuit. The IC, a chip or microchip, is a solid-state device connecting individual components to a thin semiconductor substrate. The IC then connects everything and packages it into a miniaturized electronic circuit. Integrated circuits are found in various electronic devices, such as automobiles, airplanes, microwaves, televisions, smartphones, and computers.

Integrated circuits combine transistors and diodes with resistors, capacitors, and other components (microchips).

The current in a solid-state component is confined to solid elements and compounds explicitly designed to switch and amplify the current, which can flow in one of two ways: as negatively charged electron deficiencies, known as holes, or as positively charged electron deficiencies, known as holes. The current in some semiconductors is mainly made up of electrons, while in others, it is mostly made up of holes. Charge carriers include both electrons and holes.

Solid-state memory

Because solid-state systems have no moving parts, they are more portable, efficient, and long-lasting than their mechanical counterparts. Solid-state drives (SSDs) of today, for example, typically use NAND chips to provide flash-based storage.

Data is stored on integrated circuits rather than mechanical components. This starkly contrasts to the hard-disk drive (HDD), which reads and writes data using spinning disks and other moving parts.

Source: www.techtarget.com