Introduction to Microelectronics to Nanoelectronics

Design and Technology

Manoj Kumar Majumder, Vijay Rao Kumbhare, Aditya Japa, Brajesh Kumar Kaushik

• Publisher: CRC Press
• Year: 2020
• ISBN:
  9781000223095
• Edition: 1
• Topic: Scienze fisiche
• Subtopic: Fisica

Focussing on micro- and nanoelectronics design and technology, this book provides thorough analysis and demonstration, starting from semiconductor devices to VLSI fabrication, designing (analog and digital), on-chip interconnect modeling culminating with emerging non-silicon/ nano devices. It gives detailed description of both theoretical as well as industry standard HSPICE, Verilog, Cadence simulation based real-time modeling approach with focus on fabrication of bulk and nano-devices. Each chapter of this proposed title starts with a brief introduction of the presented topic and ends with a summary indicating the futuristic aspect including practice questions. Aimed at researchers and senior undergraduate/graduate students in electrical and electronics engineering, microelectronics, nanoelectronics and nanotechnology, this book:

• 
  
  

• Provides broad and comprehensive coverage from Microelectronics to Nanoelectronics including design in analog and digital electronics.

• 
  
  

• Includes HDL, and VLSI design going into the nanoelectronics arena.

• 
  
  

• Discusses devices, circuit analysis, design methodology, and real-time simulation based on industry standard HSPICE tool.

• 
  
  

• Explores emerging devices such as FinFETs, Tunnel FETs (TFETs) and CNTFETs including their circuit co-designing.
• Covers real time illustration using industry standard Verilog, Cadence and Synopsys simulations.

1 Semiconductor Physics and Devices

1.1 Introduction

Semiconductors have revolutionized the field of electronics and play a prominent role in our day-to-day life. The seed of development of these modern solid-state semiconductors dates back to early 1930s. Each electronic device that we see around is made up of semiconductors. We wouldn’t have been able to achieve these remarkable results without them.

1.1.1 Conduction in Solids

The form in which matter exists is called the state of matter. Matter exists in many distinct states of which three states are well known and important. They are solids, liquids, and gases, and other states include plasma, Bose–Einstein condensates, degenerate matter, photonic matter, etc. These other states occur only in extreme conditions of pressure, temperature, and energy. The main difference in the structure of each state lies in the densities of the particles. The density of particles is highest in solids and lowest in gases. Figure 1.1 shows the alignment of particles in different states of matter and the processes through which we can convert one state of matter to another.

FIGURE 1.1 Alignment of particles in different states of matter.

Solids are further classified into three types based upon the distance between their valence band and conduction band. This distance is called the bandgap [1]. The electrical conductivity of the substance depends upon the bandgap of the material. We say that the substance is able to conduct if there are free electrons in the conduction band. When energy is supplied to the elements, the electrons in the valence band get excited and jump up into the conduction band, allowing the passage of electricity through the substance. In conductive materials, no bandgap exists, due to which electrons can move easily between their valence band and the conduction band. Unlike conductors, insulators have a huge bandgap between the conduction and the valence band. The valence band remains full since no movement of electrons occurs, and as a result, the conduction band remains empty as well. In semiconductor materials, the bandgap between the conduction band and the valence band is smaller. At room temperature, there is enough energy accessible to displace a few electrons from the valence band into the conduction band. As temperature increases, the conductivity of a semiconductor material increases. Figure 1.2 shows the bandgaps in conductors, semiconductors, and insulators, respectively.

FIGURE 1.2 Band diagrams of conductors, semiconductors, and insulators.

1.1.2 Conductors, Insulators, and Semiconductors

This subsection provides a detailed description of different material properties.

1.1.2.1 Conductors

The substances that allow electricity to pass through them are called conductors. Metals such as gold, silver, and copper are good examples of conductors. These substances have free electrons in their outermost orbit. There is no or very little distance between the conduction band and the valence band.

Properties of Conductors

• Conductors have high electrical and thermal conductivities.
• In steady states, they obey Ohm’s law.
• They have a positive temperature coefficient, i.e., their resistance increases with an increase in temperature.
• They obey Wiedemann–Franz law, according to which the ratio of thermal and electrical c...