Compound Semiconductor Devices

Calendar

LEC #	TOPICS	KEY DATES
1	Compound Semiconductors: The families (III-V’s, II-VI’s, IV-VI’s, IV-IV’s), alloys, Eg vs a; band structures (E vs k; Γ, L, X minima; direct vs. indirect gaps); crystal lattices, electrical properties, optical properties; trends in properties and the periodic table. The useful compounds.
2	Metal-Semiconductor Interfaces (Schottky Barriers): The compound semiconductor surface; Fermi level pinning. Theories of barrier formation and of current flow; diffusive vs. ballistic flow; contrasts with p-n diodes. Theory and practice of ohmic contacts.
3	Heterostructures: E-x Profiles: ΔEc, ΔEv, Ec(x), Ev(x); no(x), po(x); modulation doping. Conduction parallel to heterojunction; mobility in semiconductors and carrier scattering mechanisms.	Problem Set 1 Out
4	Heterojunctions: Conduction normal to junction: I-V models and characteristics. Theory of graded layers; creation of internal carrier-specific fields.
5	Quantum Effect Structures: Quantum wells: theory, fabrication, observation (verification), and application. Quantum wires and dots.
6	Quantum Effect Structures (contd.): Coupled quantum structures: super lattices. Resonant tunneling: RTD structure and concept. I-V theory. Related devices and applications: RTD-load logic, memory cells.	Problem Set 1 Due
7	Epitaxy: Concerns / constraints — lattice-matched systems; strained layers (pseudomorphic) — limits of thickness; impact of strain on bands, properties.
8	Epitaxy (contd.): Techniques — MOCVD, CBE, MBE (MO, GS, & SS). Device Processing: Etching. Surface passivation; dielectric films.	Problem Set 2 Out
9	MESFETs: Basic concept, models for terminal characteristics; accounting for velocity saturation. Dynamic models: large signal switching transients; small signal, high f models. Fabrication sequences; application-specific designs (power, digital, low noise microwave).
10	MESFET Digital Logic Families: Performance criteria for logic. Logic families: normally-on logic (FL, BFL, SDFL); normally-off logic (DCFL); comparison offamilies; examples of fabrication sequences; performance data; state-of-the-art commercially.** Microwave Linear ICs**: Building blocks, amplifier stages, waveguides, lumped elements. MMIC and wireless technologies.	Problem Set 2 Due
11	HFETs (Doped Channel): Concept; I-V model including velocity saturation; gate 2 characteristics; output conductance; applications of strained layers. HFETs (Intrinsic Gate): HIGFET’s — basic device, features, theory. Complementary structures for logic.
12	HFETs (Modulation Doped): MODFETs — basic device, theory. Deep level problem (transconductance collapse); pseudomorphic solution.  Telecommunications applications — key features: gain, bandwidth, linearly, noise.
13	HBTs: Concept: emitter efficiency, base transport, base resistance, junction capacitance. HJ collector and collector-up refinements. Applications of graded layers: control of HJ spikes; ballistic injection; problems with upper-valley minima.	Problem Set 3 Out
14	HBTs (contd.): State-of-the-art commercial HBT technologies (III-V and IV-IV).
15	Light Emission and Absorption: Basic theory. Direct vs. indirect gap. Band-to-band and band-to-impurity transistions.	Problem Set 3 Due
16	Dielectric Waveguides / Photonic Crystals: Basics of optical cavities and waveguides. Photonic crystal concepts, structures, issues.
17	Light Emitting Diodes: LEDs — structure, materials, characteristics (i-v, l-i, l-l), performance. Light extraction, current spreading, photon recycling.
18	LEDs (contd.): Applications in displays and illumination — considerations, current practice, recent commercial developments.
19	Laser Diodes: Feedback and stimulated emission. Cavity design; double heterostructure concept. Quantum well, wire, dot active regions. Strained layers; pseudomorphic active regions.
20/21	Laser Diodes (contd.): In-plane lasers: double heterostructure, quantum well, multi-contact, surface emitting. Vertical cavity surface emitting lasers (VCSELs). Modulation and control of emission. New structures and material systems including blue-green lasers and cascade lasers.
22	Detectors: Structure and theory of basic types: p-i-n (conventional and unicarrier), APD, Schottky diode, m-s-m; resonant cavity concepts.
23	Detectors (contd.): Vertical vs. in-plane geometries. Quantum well intersubband photodetectors.
24	Modulators: Multiple quantum well structures, quantum confined Stark effect; SEED. Waveguide couplers, switches, modulators. Photonic Circuits, Optoelectronic Integrated Circuits (OEICs): Integration goals and challenges; applications.
25	OEICs (contd.): Approaches to integration and current state-of-the-art. Epitaxial stacks, multiple-epitaxial runs, epitaxy on processed electronics (GaAs-on-Si, GaAs-on-GaAs, Si-on-GaAs). Bonding. Hybrid integration. Self-assembly.
26	Quantum Effect Devices: Electron waveguides, single electron transistors, etc.
27	Device Research Conference Preview / Industrial Overview: What’s new and exciting this year in research and in the marketplace?