
Lecture Description
- The CosmoLearning Team
Course Index
- Introduction to Basic Concepts
- Requirements of High Speed Devices, Circuits & Materials
- Classifications & Properties of Compound Semiconductors
- Temary Compound Semiconductor and their Applications I
- Temary Compound Semiconductor and their Applications II
- Crystal Structures in Gallium Arsenide (GaAs)
- Dopants and impurities in GaAs and InP
- Brief Overview of GaAs Technology for High Speed Devices
- Epitaxial Techniques for GaAs High Speed Devices
- MBE and LPE for GaAs Epitaxy
- GaAs and InP Devices for Microelectronics
- Metal Semiconductor Contacts for MESFET I
- Metal Semiconductor contacts for MESFET II
- Metal Semiconductor contacts for MESFET III
- Ohmic Contacts on Semiconductors
- Fermi Level Pinning & Schottky Barrier Diodes
- Schottky Barrier Diode
- Schottky Barrier Diodes
- Causes of Non-Idealities-Schottky Barrier Diodes
- MESFET: Operation & I-V Characteristics
- MESFET: I-V Characteristics Shockley's Model
- MESFET: Shockley's Model and Velocity Saturation
- MESFET: Velocity Saturation Effect on Drain Current Saturation
- MESFET: Drain Current Saturation IDS due to Velocity Saturation
- MESFET: Effects of Channel Length and Gate Length on IDS and gm
- MESFET: Effects of Velocity Saturation and Velocity Field Characteristics
- MESFET: Velocity Field Characteristics - Overshoot Effects
- Velocity Overshoot Effect and Self-aligned MESFET SAINT
- Self-aligned MESFET-SAINT: Threshold Voltage and Sub Threshold Current
- Hetero Junctions
- Hetero Junctions & High-Electron Mobility Transistor (HEMT) I
- Hetero Junctions & High-Electron Mobility Transistor (HEMT) II
- High Electron Mobility Transistor
- HEMT-off Voltage
- HEMT 1-V Characteristics and Transconductance
- Indium Phosphide Based HEMT
- Pseudomorphic HEMT
- Hetrojunction Bipolar Transistors (HBT) I
- Hetrojunction Bipolar Transistors(HBT) II
- Hetrojunction Bipolar Transistors(HBT) III
- Hetrojunction Bipolar Transistors(HBT) IV
Course Description
1. Important parameters governing the high speed performance of devices and circuits:-
Transit time of charge carriers, junction capacitances, ON-resistances and their dependence on the device geometry and size, carrier mobility, doping concentration and temperature. Contact resistance and interconnection/interlayer capacitances in the Integrated Electronics Circuits. (4 hours)
2. Silicon based MOSFET and BJT circuits for high speed operation and their limitations:-
Emitter coupled Logic (ECL) and CMOS Logic circuits with scaled down devices. Silicon On Insulator (SOI) wafer preparation methods and SOI based devices and SOICMOS circuits for high speed low power applications. (8 hours)
3. Materials for high speed devices and circuits:-
Merits of III –V binary and ternary compound semiconductors (GaAs, InP, InGaAs, AlGaAs ETC.), silicon-germanium alloys and silicon carbide for high speed devices, as compared to silicon based devices. Brief outline of the crystal structure, dopants and electrical properties such as carrier mobility, velocity versus electric field characteristics of these materials. Material and device process technique with these III-V and IV – IV semiconductors.
(8 hours)
4. Metal semiconductor contacts and Metal Insulator Semiconductor and MOS devices:
Native oxides of Compound semiconductors for MOS devices and the interface state density related issues. Metal semiconductor contacts, Schottky barrier diode. Thermionic Emission model for current transport and current-voltage (I-V) characteristics. Effect of interface states and interfacial thin electric layer on the Schottky barrier height and the I-V characteristics. (6 hours)
5. Metal semiconductor Field Effect Transistors (MESFETs):
Pinch off voltage and threshold voltage of MESFETs. D.C. characteristics and analysis of drain current. Velocity overshoot effects and the related advantages of GaAs, InP and GaN based devices for high speed operation. Sub threshold characteristics, short channel effects and the performance of scaled down devices. (6 hours)
6. High Electron Mobility Transistors (HEMT):
Hetero-junction devices. The generic Modulation Doped FET(MODFET) structure for high electron mobility realization. Principle of operation and the unique features of HEMT. InGaAs/InP HEMT structures. ( 6 hours)
7. Hetero junction Bipolar transistors (HBTs):
Principle of operation and the benefits of hetero junction BJT for high speed applications. GaAs and InP based HBT device structure and the surface passivation for stable high gain high frequency performance. SiGe HBTs and the concept of strained layer devices. (6 hours)
8. High speed Circuits:
GaAs Digital Integrated Circuits for high speed operation- Direct Coupled Field Effect Transistor Logic (DCFL), Schottky Diode FET Logic (SDFL), Buffered FET Logic(BFL). GaAs FET Amplifiers. Monolithic Microwave Integrated Circuits (MMICs) (4 hours) 9. High Frequency resonant – tunneling devices. Resonant-tunneling hot electron transistors and circuits. (2 hours)