Nano Electronics (EC-702 (C)) - Important Questions

Define field emission. Derive the Fowler–Nordheim equation for the field emission current density $J$ from a metal surface and discuss the dependence of $J$ on the electric field and work function. Comment on practical factors that affect field emission in nanoelectronic devices.

Explain gate–oxide tunneling in MOS structures. Distinguish between direct tunneling and Fowler–Nordheim tunneling, explain the role of oxide thickness, and discuss the effects of gate–oxide tunneling on device performance and reliability.

Discuss hot electron effects in nano MOSFETs. Explain mechanisms that generate hot carriers, their impact on device characteristics and reliability, and common mitigation techniques used in device design.

Describe the principle of the Scanning Tunneling Microscope (STM). Derive the expression showing the dependence of the tunneling current on the tip–sample separation and discuss how STM is used for imaging and spectroscopic measurements at the atomic scale.

Explain double barrier tunneling and the operation of a Resonant Tunneling Diode (RTD). Describe the origin of resonant states, explain negative differential resistance, and derive the resonance condition qualitatively.

Discuss nanoscale MOSFETs and FinFETs. Explain the key short–channel effects at nanoscale, the electrostatic advantages of FinFET geometry over planar MOSFETs, and how scaling affects threshold voltage control and leakage.

Explain charge and energy quantization in single electron devices. Define Coulomb blockade and charging energy $E_{C}$, and describe the basic operation and characteristics of a single electron transistor (SET).