6.012 ELECTRONIC DEVICES AND CIRCUITS Schedule -- Fall 1995 (8/31/95 version) Recitation 1 -- Wednesday, Sept. 6: Review of 6.002 models for BJT. Discussion of models and modeling; motivate need to go beyond empirical descriptions. Large and small signal descriptions and 6.012 signal notation. Lecture 1-- Thursday, Sept. 7: Introduction/Modeling. Intrinsic semiconductors, bond structure, holes and electrons; n i (T). Dopants -- donors and acceptors. Recitation 2 -- Friday, Sept. 8: Basic concepts: drift, drift velocity vs. field, mobility; electrostatics (8.02), Poisson's equation; ρ, E, φ. Problem Set #1 out (equilibrium carrier concentrations, transport properties, Hall effect). Lecture 2 -- Tuesday, Sept. 12: n o and p o in extrinsic (doped) semiconductor: Thermal equilibrium, detailed balance, n o p o product; n o, p o given N A, N D. Recitation 3 -- Wednesday, Sept. 13: Calculations of n o, p o in variously doped examples. Typical values of mobility, conductivity, resistivity. Comparison with metals, insulators. Sheet resistance concept. Lecture 3 -- Thursday, Sept. 14: Uniform excitation: Review drift; concept of n-type and p-type. Uniform optical injection. Low level injection. Minority carrier lifetimes. Homogeneous solution. Recitation 4 -- Friday, Sept. 15: Population transients. Responses to various common waveforms. Analogy with RC circuits. Problem Set #1 due; Problem Set #2 out (population transient calculations, photoconductivity, drift). Lecture 4 -- Tuesday, Sept. 19: Non-uniform injection and/or doping. Diffusion. Continuity/conservation. The five basic equations. Recitation 5 -- Wednesday, Sept. 20: Diffusion video. Haynes-Shockley video. Lecture 5 -- Thursday, Sept. 21: Linearization and decoupling of 5 basic equations in flow problem regime: quasineutrality, Debye length, L Dx, and dielectric relaxation time, τ D ; minority carrier flow by diffusion. Diffusion equation(s) for n': general solutions; boundary conditions; procedure to find n, p, J e, J h, E x having n'. Recitation 6 -- Friday, Sept. 22: Example of injection in middle of a bar; short-base and long-base limits. Boundary conditions; continuity at internal boundaries. Infinite lifetime approximation, integral solution, nature of profiles. Problem Set #2 due; Problem Set #3 out (diffusion, flow problems, electrostatic potential). Lecture 6 -- Tuesday, Sept. 23: Non-uniformly doped material in thermal equilibrium. Electrostatic potential (using Einstein relation); Poisson equation. n o (x), p o (x), φ(x) when doping varies slowly; quasineutral approximation; extrinsic Debye length, L Dx. Begin abrupt p-n junction. 1
Recitation 7 -- Wednesday, Sept. 27: More (final) discussion and solutions of flow problems; infinite lifetime example with uniform injection over some portion(s). Lecture 7 -- Thursday, Sept. 28: Abrupt p-n junction in thermal equilibrium; depletion approximation. Expressions for W, x n x p, E pk. Reverse bias. Charge storage associated with SCL. Recitation 8 -- Friday, Sept. 29: Typical values of φ; emphasize weak dependence on n o, p o ; show 60 mv per decade dependance. Typical values for x n, x p, E pk, φ b in moderately assymetrical abrupt junction. φ(x) around a circuit through contacts. Problem Set #3 due; Problem Set #4 out (abrupt p-n junctions, electrostatics, current flow in p-n diodes). Lecture 8 -- Tuesday, Oct. 3: Forward biased abrupt p-n junction. Minority carrier concentrations and equilibrium across space charge layer; current flow. Derivation of I-V expression. Recitation 9 -- Wednesday, Oct. 4: Plots of carrier populations and current densities through forward and reverse biased short and long base p-n diodes. Note injection is into lightly doped side. Lecture 9 -- Thursday, Oct. 5: Light emitting diodes. Illuminated p-n diodes; superposition; solar cells and photodiodes. Begin introduction of bipolar transistor. Recitation 10 -- Friday, Oct. 6: Charge storage in biased p-n junctions; depletion and diffusion capacitances. Problem Set #4 due; Problem Set #5 out (depletion and diffusion capacitances, photodetectors). Review 1 -- Wednesday, Oct. 11: No formal recitation sessions. Instructors will be available to answer questions and review issues for the quiz. Quiz 1 -- Wednesday, Oct. 11, 7 to 9 pm, Rm 50-340 (Walker Memorial quiz room). Open book. Covering material through 10/4/95 and Problem Set #4. Lecture 10 -- Thursday, Oct. 12: Bipolar junction transistor; Ebers-Moll model. Approximate model valid in forward active region. β-model. npn/pnp. Recitation 11-- Friday, Oct. 13: Review Ebers-Moll model. Use large signal BJT model to calculate transfer characteristic of common emitter amplifier. Problem Set #5 due; Problem Set #6 out (BJT large signal characteristics, MOS capacitor). Lecture 11 -- Tuesday, Oct. 17: MOS structures. Discussion of accumulation, depletion, inversion. Application of depletion approximation to MOS capacitor to relate channel charges to gate voltage. C-V relationship for MOS structure. Recitation 12 -- Wednesday, Oct. 18: Review accumulation, depletion, and inversion in MOS, and model relating channel charge to gate voltage in excess of threshold. 2
Lecture 12 -- Thursday, Oct. 19: Gradual channel approximation for MOSFET i-v characteristics; quadratic approximation. Features of characteristics; regions of operation. Discussion of pinch-off. Recitation 13-- Friday, Oct. 20: Possible MOSFET device types: n- and p-channel, enhancement and depletion mode. Use of large signal model to calculate transfer characteristics of common-source inverter. Problem Set #6 due; Problem Set #7 out (MOSFET static large signal characteristics, MOSFET types, inverter transfer characteristics). Lecture 13 -- Tuesday, Oct. 24: Linearization of models for small signal operation about bias point. Begin with incremental model for diode. Accounting for charge stores in a p-n junction diode; diffusion and depletion capacitances. Recitation 14 -- Wednesday, Oct. 25: Additional comments on linearization and incremental modeling; further discussion of depletion and diffusion capacitances. Lecture 14 -- Thursday, Oct. 26: Incremental model for BJT; hybrid-π. Incremental model for MOSFET. Expressions for parameters in various operating regions. g o, Early voltage. Examination of charge storage elements (i.e., capacitances). Recitation 15 -- Friday, Oct. 27: Final discussion of small signal, linear incremental models. Comparison of MOSFET and BJT; typical g m values. Importance of stable bias point. Problem Set #7 due; Problem Set #8 out (incremental transistor models, simple amplifiers). Lecture 15 -- Tuesday, Oct. 31: Begin transistor amplifiers: capacitive coupling; concept of mid-band frequency range, common-emitter/-source as example. Performance metrics: voltage, current, and power gains; input and output resistances. Recitation 16 -- Wednesday, Nov. 1: Common-base/-gate and emitter-/sourcefollower amplifier stages. Degenerate-emitter/-source stages; analysis and features. Lecture 16 -- Thursday, Nov. 2: Achieving maximum gain. Non-linear and active loads. Biasing; importance of bias point stability. Recitation 17 -- Friday, Nov. 3: Continue discussion of single-transistor amplifier stages. Problem Set #8 due; Problem Set #9 out (amplifier analysis, incl. differential amplifiers). Lecture 17-- Tuesday, Nov. 7: Differential amplifiers. Qualitative analysis. Large signal analysis; transfer characteristics. Review 2 -- Wednesday, Nov. 8: No formal recitation sessions. Instructors will be available to answer questions and review issues for the quiz. 3
Quiz 2 -- Wednesday, Nov. 8, 7 to 9 pm, Rms 4-270 (a-l) and 4-370 (m-z). Open book. Covering material through 11/1/95 and Problem Set #8. Lecture 18 -- Thursday, Nov. 9: Incremental analysis of differential amplifiers. Halfcircuit analysis techniques. Begin multi-stage amplifier design; issues of bias, loading, stage choice. Lecture 19 -- Tuesday, Nov. 14: Multi-stage amplifiers cont.; compare design with single transistor stages and differential stages, and with direct and capacitive coupling. Introduce some of standard mult-transistor stages. Design Problem out. Recitation 18 -- Wednesday, Nov. 15: Examples of analysis using half-circuit techniques. Calculation of input and output resistances. Determination of common- and difference-mode voltage swings. Problem Set #9 due. Lecture 20 -- Thursday, Nov. 16: Active loads. Current mirrors. Double- to singleended output conversion. Examination of commercial designs. Recitation 19 -- Friday, Nov. 17: Overview of design problem circuit. Understanding the performance specifications. General analysis approach. Current source circuits for biasing. Lecture 21 -- Tuesday, Nov. 21: Review of depletion and diffusion capacitances and high frequency MOSFET and BJT models. High frequency gain of commonemitter/-source stage. Miller capacitance. Recitation 20 -- Wednesday, Nov. 22: High frequency analysis of common-gate and source-follower stages. Cascode. Lecture 22 -- Tuesday, Nov. 28: High frequency analysis of multi-stage amplifiers. Intrinsic limits to transistor high frequency performance: ω α, ω β, ω t. Limits of quasi-static approximation. Recitation 21 -- Wednesday, Nov. 29: IC Fabrication technology; Berkeley CMOS fabrication video. Discussion of any remaining design problem issues. Lecture 23 -- Thursday, Nov. 30: Basic inverters as building blocks for digital logic, memory; performance critieria. Begin MOS logic; review calculation of MOSFET inverter transfer characteristics. Recitation 22 -- Friday, Dec. 1: Large signal switching of p-n junction diode; charge storage in forward biased junctions. Estimating switching time from current and charge store. Design Problem due by 5 pm in Room 13-3058; Problem Set #10 out (high frequency analysis, transient responses). Lecture 24 -- Tuesday, Dec. 5: MOSFET inverter stages; comparison of various loads in logic context -- logic swing, speed, power. Emphasis on CMOS. Recitation 23 -- Wednesday, Dec. 6: Bipolar logic families: TTL, ECL. 4
Lecture 25-- Thursday, Dec. 7: CMOS design examples. Analog and digital circuits. Discussion of scaling, speed, power, and fabrication economics. Concept and role of BiCMOS. Recitation 24 -- Friday, Dec. 8: MOSFET memory cells; isolated MOS capacitor, CCDs. Problem Set #10 due. Lecture 26 -- Tuesday, Dec. 12: Overview of current state of the art; present and future trends in integrated electronics and optoelectronics. Review of course and suggestions for follow-on subjects. Recitation 25 -- Wednesday, Dec. 13: Review session. Looking back on the semester. Final 1 -- To be scheduled by registrar. Open book. Covering all material in subject. 5