Back to Sentaurus TCAD

HEMT Device Structure Interactive Demo

Step-by-Step Device Visualization & Simulation

1. Device Structure Setup

Layer-by-Layer Build Control

Precise Layer Specifications

Layer Material Thickness Doping Purpose
Substrate 4H-SiC 350 μm n-type: 5×10¹⁸ cm⁻³ Thermal management, structural support
Buffer AlN/GaN 2 μm Undoped Lattice mismatch accommodation
Channel GaN 1.5 μm Undoped 2DEG formation, current conduction
Barrier In₀.₁₇Al₀.₈₃N 15 nm Undoped 2DEG confinement, gate control
Cap GaN 2 nm Undoped Surface protection, contact formation

2. Architecture Variants: Enhancement vs Depletion Mode

Depletion Mode (D-HEMT)

  • Normally ON at Vgs = 0V
  • Negative gate voltage required to turn OFF
  • 2DEG present without gate bias
  • Vth typically -2V to -5V
  • Higher transconductance

Enhancement Mode (E-HEMT)

  • Normally OFF at Vgs = 0V
  • Positive gate voltage required to turn ON
  • 2DEG depleted under gate at zero bias
  • Vth typically +1V to +3V
  • Safer for power applications

Key Differences

Parameter Depletion Mode Enhancement Mode
Gate Structure Standard Schottky Recessed gate / p-GaN gate
2DEG at Vgs=0 Present (High density) Depleted under gate
Threshold Voltage -2V to -5V +1V to +3V
Drive Circuit Negative bias required Standard positive drive
Fail-safe Operation No (Normally ON) Yes (Normally OFF)

3. 2DEG Formation and Control

2DEG Density

1.2 × 10¹³ cm⁻²

Channel Status

ON

Drain Current

0 mA