6.772 | Spring 2003 | Graduate

Compound Semiconductor Devices

Lecture Notes

The white board files provided below correspond to lecture content captured with an electronic white board during class.

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. (PDF)
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. (PDF)

White Board (PDF)

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. (PDF)

White Board (PDF)

4 Heterojunctions: Conduction normal to junction: I-V models and characteristics. Theory of graded layers; creation of internal carrier-specific fields. (PDF)
Semiconductor Physics Review - Outline (PDF)
Band Profiles at HJs (XLS)

White Board (PDF)

5 Quantum Effect Structures: Quantum wells: theory, fabrication, observation (verification), and application. Quantum wires and dots. (PDF)

White Board (PDF)

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. (PDF)
7 Epitaxy: Concerns / constraints — lattice-matched systems; strained layers (pseudomorphic) — limits of thickness; impact of strain on bands, properties. (PDF - 1.1 MB)
8 Epitaxy (contd.): Techniques — MOCVD, CBE, MBE (MO, GS, & SS).

Device Processing: Etching. Surface passivation; dielectric films.
Part 1 PDF)
Part 2 (PDF - 1.1 MB)

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). (PDF)
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. (PDF)

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. (PDF)

12 HFETs (Modulation Doped): MODFETs — basic device, theory. Deep level problem (transconductance collapse); pseudomorphic solution.  Telecommunications applications — key features: gain, bandwidth, linearly, noise. (PDF)
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. (PDF)

White Board (PDF- 1.3 MB)

14 HBTs (contd.): State-of-the-art commercial HBT technologies (III-V and IV-IV). (PDF - 2.4 MB)

White Board (PDF)

15 Light Emission and Absorption: Basic theory. Direct vs. indirect gap. Band-to-band and band-to-impurity transistions. (PDF)

White Board (PDF - 2.2 MB)

16 Dielectric Waveguides / Photonic Crystals: Basics of optical cavities and waveguides. Photonic crystal concepts, structures, issues. (PDF)

White Board (PDF - 3.0 MB)

17 Light Emitting Diodes: LEDs — structure, materials, characteristics (i-v, l-i, l-l), performance. Light extraction, current spreading, photon recycling. (PDF)

White Board (PDF - 1.8 MB)

18 LEDs (contd.): Applications in displays and illumination — considerations, current practice, recent commercial developments. (PDF - 1.7 MB)

White Board (PDF - 2.0 MB)

19 Laser Diodes: Feedback and stimulated emission. Cavity design; double heterostructure concept. Quantum well, wire, dot active regions. Strained layers; pseudomorphic active regions. (PDF)

White Board (PDF)

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.
Part 1 (PDF - 1.2 MB)
Part 2 (PDF)

White Board (PDF - 1.4 MB

22 Detectors: Structure and theory of basic types: p-i-n (conventional and unicarrier), APD, Schottky diode, m-s-m; resonant cavity concepts. (PDF - 1.9 MB)

White Board (PDF - 1.9 MB)

23 Detectors (contd.): Vertical vs. in-plane geometries. Quantum well intersubband photodetectors. (PDF)

White Board (PDF - 2.4 MB)

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. (PDF)

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. (PDF - 3.5 MB)
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?

Course Info

As Taught In
Spring 2003
Learning Resource Types
Lecture Notes
Projects with Examples
Problem Sets with Solutions