Getting Started

This guide will help you start using the MOSFET Junction Simulator for device analysis and learning.

Interface Overview

The application has a three-panel layout:

┌──────────────────────────────────────────────────────┐
│                     Toolbar                          │
├──────────┬─────────────────────────┬────────────────┤
│          │                         │                │
│  Left    │        Main View        │    Right       │
│ Sidebar  │    (3D + 2D Views)      │   Sidebar      │
│          │                         │                │
│(Params)  │                         │   (Plots)      │
│          │                         │                │
├──────────┴─────────────────────────┴────────────────┤
│                    Status Bar                        │
└──────────────────────────────────────────────────────┘

Panel Functions

Panel	Purpose
Toolbar	Device type, physics level, view options
Left Sidebar	Device parameters, bias controls, export
Main View	3D structure, 2D cross-sections
Right Sidebar	Metrics dashboard, I-V/C-V plots, band diagram
Status Bar	Simulation status, performance info

Toolbar Controls

Control	Description
Device	Switch between nMOS and pMOS
Level	Select physics model (A/B/C)
Mode	Device or Process parameter mode
Tech	Technology node preset
T	Operating temperature
View	Colormap mode (Structure/Doping/Potential)
Auto	Auto-simulate on parameter change
Reset	Reset to default parameters
Theme	Dark/Light mode toggle

Quick Start Tutorial

Step 1: Select Device Type

Click nMOS or pMOS in the toolbar. This changes:

Setting	nMOS	pMOS
Substrate	p-type	n-type
Source/Drain	n+	p+
Bias polarity	Positive Vgs/Vds	Negative Vgs/Vds
Carriers	Electrons	Holes

Step 2: Choose Physics Level

Level	Speed	Accuracy	Best For
A	⚡ Instant	Basic	Learning, quick exploration
B	⚡ Fast	Good	Device design, SCE analysis
C	🐢 Slow	Excellent	Research, validation

Recommendation

Start with Level B for a good balance of speed and accuracy. Use Level C only when you need 2D field distributions or high accuracy.

Step 3: Select Technology Node

Pre-configured parameters are available for common nodes:

Node	Gate Length	Vdd	tox	Typical Use
180nm	180 nm	1.8V	4 nm	Legacy, analog
90nm	90 nm	1.2V	2 nm	Mature digital
45nm	45 nm	1.0V	1.5 nm	Modern CMOS
28nm	28 nm	0.9V	1.2 nm	Advanced node

Or select Custom to manually set all parameters.

Step 4: Set Device Parameters

Use the left sidebar to adjust device parameters:

Gate Stack:

• Oxide thickness ( )
• Channel length ( )
• Gate work function ( )

Channel:

• Doping concentration ( )

Source/Drain:

• Doping ( )
• Junction depth ( )
• LDD parameters

See Device Parameters for detailed explanations.

Step 5: Apply Bias Conditions

Use the Bias Controls section:

Parameter	Description	nMOS Range	pMOS Range
Vgs	Gate-to-source	0 to Vdd	0 to -Vdd
Vds	Drain-to-source	0 to Vdd	0 to -Vdd
Vbs	Body-to-source	-Vdd to 0	0 to Vdd

Step 6: Analyze Results

The right sidebar displays:

Device Metrics Dashboard:

• Threshold voltage ( )
• Subthreshold swing (SS)
• On/Off current ratio
• DIBL coefficient
• Peak transconductance ( )

Plots:

• I-V characteristics
• C-V characteristics
• Band diagram
• Transconductance plots
• Doping profile

View Controls

3D View Interaction

Action	Mouse	Result
Rotate	Left-click + drag	Orbit around device
Zoom	Scroll wheel	Zoom in/out
Pan	Right-click + drag	Move view

2D Views

The 2D panel shows cross-sections:

• Front View (X-Z): Along channel direction
• Top View (X-Y): Bird's eye view
• Side View (Y-Z): Width direction

Colormap Modes

Mode	Shows
Structure	Physical regions (substrate, channel, gate, etc.)
Doping	Net doping concentration (n-type red, p-type blue)
Net Type	Simplified n/p regions
Potential	Electrostatic potential (Level C only)
E-Field	Electric field magnitude (Level C only)

Using the Comparison Feature

To compare two device configurations:

1. Set up first device
2. Click Save State A in Comparison panel
3. Modify parameters
4. Click Save State B
5. Toggle Show Comparison to overlay results

Use Cases

• Compare different technology nodes
• Analyze SCE vs long-channel behavior
• Study parameter sensitivity

Exporting Data

Available Exports

Format	Contents
CSV (I-V)	Drain current vs bias data
CSV (C-V)	Capacitance vs gate voltage
JSON	Complete simulation state

How to Export

1. Open Export panel in left sidebar
2. Select export type
3. Click export button
4. File downloads automatically

Performance Tips

For Faster Simulation

• Use Level A or B instead of C
• Reduce mesh size (Level C settings)
• Disable auto-simulate for parameter sweeps
• Use technology presets instead of custom values

For More Accuracy

• Use Level C numerical solver
• Increase mesh density near critical regions
• Enable advanced physics options
• Use smaller convergence tolerance

Keyboard Shortcuts

Key	Action
R	Reset view
D	Toggle dark mode
A	Toggle auto-simulate
1/2/3	Switch physics level

Common Issues

Simulation Not Updating

• Check if "Auto" is enabled
• For Level C, wait for completion (check status bar)
• Try clicking "Simulate" manually

Unexpected Results

• Verify bias polarities match device type
• Check that parameters are physically reasonable
• Start from a technology preset

Level C Too Slow

• Reduce mesh size
• Use coarser tolerance
• Consider Level B for initial exploration

Next Steps

• Read Device Parameters for parameter details
• Explore Physics Overview to understand the models
• Try different technology nodes and compare results