Figure 2 Covalent bonding of the silicon Atomĥ Intrinsic materials are those semiconductors that have been carefully refined A bonding of atoms, strengthened by the sharing of electrons, is called covalent bonding Figure 1 Atomic structure: (a) germanium (b) silicon. Both Ge and Si are referred to as tetravalent atoms because they each have four valence electrons. In a pure germanium or silicon crystal these 4 valence electrons are bonded to 4 adjoining atoms, as shown in Fig. These 4 valence electrons is lower than that required for any other electron in the structure. In each case, there are 4 electrons in the outermost(valence) shell.Ĥ The potential (ionization potential) required to remove any one of 1a, the germanium atom has 32 orbiting electrons, while silicon has 14 orbiting electrons. A semiconductor, therefore, is a material that has a conductivity level somewhere between the extremes of an insulator and a conductor. An insulator is a material that offers a very low level of conductivity under pressure from an applied voltage source. Semiconductor Materials :Ge, Si, Ga As : The term conductor is applied to any material that will support a generous flow of charge when a voltage source of limited magnitude is applied across its terminals. The first device to be introduced here is the simplest of all electronic devices, yet has a range of applications that seems endless. The first integrated circuit (IC) working at Texas instrument in 1958 Today, the intel pentium 4 processor has more than 42 million transistors. Complete systems now appear on wafers thousands of times smaller than the single element of earlier networks. Semiconductor Diodes The miniaturization that has resulted leaves us to wonder about its limits. Jimmie J.”Electronic Devices & Circuits” Contents: Semiconductor Diodes Chapter 1 Diode Applications Chapter 2 Bipolar Junction Transistors Chapter 3 DC Biasing – BJTs Chapter 4 BJT Smalll- signal Analysis Chapter 5ġ.1 Introduction 1.2 Semiconductor Materials :Ge, Si, Ga As 1.3 Energy Levels 1.4 Extrinsic Materials-n- and p-Type 1.5 Semiconductor Diode 1.6 Ideal Versus practical 1.7 Diode Equivalent Circuits 1.8 Transition and Diffusion Capacitance 1.9 Reverse Recovery Time 1.10 Zener Diodes 1.15 Light-Emitting Diodes (LEDs) & other types of diodesģ 1. Jacob Millman & Arvin Grabel “Microelectronics” 4. Millman & Halikas “ Electronic Devices & Circuits” 3. Electronic Devices and Circuit theory By: Robert L, Boylested & Nashelsky 2. Ministry of teaching& high education Al- Mustansiriya University College of engineering Computer & Software engineering 1' class Electronic 1 Electronic I References: 1. Millman & Halikas “ Electronic Devices & Circuits” Millman & Halikas “ Electronic Devices & Circuits”"- Presentation transcript:ġ 2.
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