⭐ When you enter the simulation section, a guided tour will appear. It is strongly recommended that you take the tour for the first time, as it provides step-by-step instructions to help you understand the experiment thoroughly. The tour also introduces you to the various controls, features, and interface elements, making it easier for you to navigate and explore the experiment effectively.

Part 1: Interactive Simulation

Understanding the MOS Structure

The simulation displays a cross-sectional view of a MOS capacitor with three main layers:

• Metal Gate (top, dark gray): Aluminum, Polysilicon, or Gold
• Oxide Layer (middle, yellow): Silicon dioxide (SiO₂) insulator
• Semiconductor Substrate (bottom, large area): p-type or n-type Silicon

Task 1: Exploring Operating Modes

Objective: Understand how gate voltage controls the three fundamental operating modes of a MOS capacitor.

1. Observe the initial state with gate voltage at 0V (Flat-band condition)
2. Apply negative gate voltage (-4V to -1V):
   • Watch the Accumulation Layer (green) appear
   • Observe majority carriers accumulating at the oxide interface
   • Note the mode indicator shows "ACCUMULATION" (green)
3. Apply small positive gate voltage (0V to threshold voltage ~0.7V):
   • Watch the Depletion Region (gray dashed) expand
   • See mobile carriers being pushed away from the surface
   • Note the mode indicator shows "DEPLETION" (red)
4. Apply large positive gate voltage (above threshold voltage):
   • Watch the Inversion Layer (blue) form
   • Observe minority carriers creating a conductive channel
   • Note the mode indicator shows "INVERSION" (blue)

Key Parameters to Monitor:

• Operation Mode: Current operating regime
• Surface Potential: Electric potential at the semiconductor surface
• Depletion Width: Width of the charge-depleted region
• Electric Field: Strength of the electric field

Task 2: Interactive Parameter Studies

Objective: Investigate how different physical parameters affect MOS capacitor behavior.

2a: Gate Voltage Effects (Vg)

• Range: -4V to +4V
• Step: 0.1V increments
• Observations:
  • Transition points between modes
  • Changes in charge layer thickness
  • Animated charge carriers movement

2b: Body Voltage Effects (Vb) - Body Bias

• Range: -3V to +3V
• Step: 0.1V increments
• Observations:
  • Impact on threshold voltage (body effect)
  • Changes in depletion width
  • Substrate bias sensitivity

2c: Doping Concentration Effects

• Range: 10¹⁴ to 10¹⁸ cm⁻³
• Step: Logarithmic increments
• Observations:
  • Threshold voltage dependence on doping
  • Depletion width variations
  • Built-in potential changes

2d: Temperature Effects

• Range: 200K to 450K
• Step: 10K increments
• Observations:
  • Temperature coefficient of threshold voltage
  • Carrier mobility changes
  • Thermal effects on device parameters

2e: Gate Material Comparison

Available Materials:

• Aluminum (4.1 eV work function)
• p+ Polysilicon (5.0 eV work function)
• n+ Polysilicon (4.1 eV work function)
• Gold (5.1 eV work function)

Observations:

• Work function differences
• Flat-band voltage variations
• Impact on threshold voltage

2f: Substrate Type Comparison

Available Types:

• p-type Silicon: Holes as majority carriers
• n-type Silicon: Electrons as majority carriers

Observations:

• Inverted behavior between p-type and n-type
• Different accumulation/inversion voltages
• Carrier type visualization

Task 3: Quantitative Measurements

Monitor the Key Parameters section for important device characteristics:

1. Threshold Voltage (Vth): Gate voltage at which strong inversion begins
2. Flat-Band Voltage (Vfb): Gate voltage for zero band bending
3. Gate Capacitance (Cox): Oxide capacitance per unit area

Assignment: Record how these parameters change with:

• Doping concentration
• Temperature
• Gate material
• Substrate type

---

Part 2: Knowledge Challenges

Click the Challenges tab to test your understanding through interactive assessments.

Challenge 1: MOS Fundamentals Quiz

Objective: Test basic understanding of MOS capacitor physics through true/false questions.

Instructions:

1. Read each statement carefully
2. Select True or False for each question
3. Click "Check Answers" to see results
4. Use "Show Hints" if you need guidance
5. Review explanations for incorrect answers

Topics Covered:

• Operating modes (accumulation, depletion, inversion)
• Voltage effects and polarities
• Physical mechanisms
• Device parameters

Challenge 2: Fill in the Blanks

Objective: Complete sentences about MOS physics with correct technical terms.

Instructions:

1. Read each incomplete statement
2. Fill in the blank spaces with appropriate terms
3. Submit answers for automatic checking
4. Use hints for difficult questions

Challenge 3: Concept Matching

Objective: Match MOS concepts with their correct definitions or characteristics.

Instructions:

1. Click items from the left column
2. Click corresponding items from the right column
3. Lines will connect matched pairs
4. Remove incorrect matches by clicking the connection
5. Submit when all pairs are matched

Challenge 4: Advanced Concepts

Objective: Explore deeper aspects of MOS physics through multiple-choice questions.

Instructions:

1. Read each question and all options carefully
2. Select the most appropriate answer
3. Check your responses
4. Study detailed explanations

Challenge 5: Calculation Problems

Objective: Solve numerical problems related to MOS capacitor parameters.

Instructions:

1. Read each problem statement
2. Perform calculations using given values
3. Enter numerical answers in the input fields
4. Check your work against provided solutions

---

Tips for Success

1. Start with the Guided Tour to understand all features
2. Experiment systematically - change one parameter at a time
3. Record observations in the provided measurement sections
4. Use the challenges to reinforce theoretical understanding
5. Ask for hints when stuck on difficult questions
6. Review explanations for all incorrect answers