Overview

Mathematical models for the diffusion and depletion capacitance of pn junctions. Components of base current in bipolar transistors. Internal time-constants. Design equation for frequency response. High frequency equivalent circuit. HBT transistors. By deriving expressions for all device currents in terms of the charge stored in the base, expressions are derived showing the time dependence of the collector current following a step change in the base current. The mode of operation of a JFETs, MESFETs and MOSFETs. Gradual channel approximation. I-V characteristic and gm of MOSFETs. Equivalent circuits and cut-off frequency. Hetero-junctions and HEMT design. MOS technology and the role of SiO2. Accumulation, depletion and inversion in a MOS capacitor and corresponding energy band diagrams. Manufacturing approaches for reducing the effects of surface states and work function differences. Frequency response of the MOS capacitor. Basic MOS inverter based on a resistive load, saturated MOS load, depletion MOS load and CMOS; Non-volatile memories - EPROM and EAROM; Static RAM and Dynamic RAM. Charge Coupled Devices. Amorphous Si and displays.

Mathematical models for the diffusion and depletion capacitance of pn junctions. Components of base current in bipolar transistors. Internal time-constants. Design equation for frequency response. High frequency equivalent circuit. HBT transistors. By deriving expressions for all device currents in terms of the charge stored in the base, expressions are derived showing the time dependence of the collector current following a step change in the base current. The mode of operation of a JFETs, MESFETs and MOSFETs. Gradual channel approximation. I-V characteristic and gm of MOSFETs. Equivalent circuits and cut-off frequency. Hetero-junctions and HEMT design. MOS technology and the role of SiO2. Accumulation, depletion and inversion in a MOS capacitor and corresponding energy band diagrams. Manufacturing approaches for reducing the effects of surface states and work function differences. Frequency response of the MOS capacitor. Basic MOS inverter based on a resistive load, saturated MOS load, depletion MOS load and CMOS; Non-volatile memories - EPROM and EAROM; Static RAM and Dynamic RAM. Charge Coupled Devices. Amorphous Si and displays.

Assessment Strategy

-threshold -Equivalent to 40%. Uses key areas of theory or knowledge to meet the Learning Outcomes of the module. Is able to formulate an appropriate solution to accurately solve tasks and questions. Can identify individual aspects, but lacks an awareness of links between them and the wider contexts. Outputs can be understood, but lack structure and/or coherence.

-good -Equivalent to the range 60%-69%. Is able to analyse a task or problem to decide which aspects of theory and knowledge to apply. Solutions are of a workable quality, demonstrating understanding of underlying principles. Major themes can be linked appropriately but may not be able to extend this to individual aspects. Outputs are readily understood, with an appropriate structure but may lack sophistication.

-excellent -Equivalent to the range 70%+. Assemble critically evaluated, relevant areas of knowledge and theory to construct professional-level solutions to tasks and questions presented. Is able to cross-link themes and aspects to draw considered conclusions. Presents outputs in a cohesive, accurate, and efficient manner.

Learning Outcomes

• Know the various devices based on the MOS structure.

• Understand and explain the physical processes occurring in MOS capacitors and the role of surface states and work function on the threshold voltage.

• Understand charge control analysis in relation to bipolar transistor switching.

• Understand the operation of JFETs, MESFETs, MOSFETs and HEMTs

• Understand the physical processes controlling the frequency response of bipolar transistors.