Gated diode is a test structure for junction characterization — combining a PN junction with a gate electrode to enable comprehensive characterization of junction properties, leakage mechanisms, and interface quality in semiconductor devices.

What Is Gated Diode?

• Definition: PN junction with gate electrode for enhanced characterization.
• Structure: PN diode with MOS gate over junction region.
• Advantage: Gate control enables detailed junction analysis.

Why Gated Diode?

• Junction Characterization: Measure junction depth, doping, leakage.
• Leakage Mechanisms: Identify bulk vs. surface leakage.
• Gate Control: Modulate surface to isolate leakage sources.
• Process Monitor: Track junction formation quality.
• Reliability: Assess junction breakdown and degradation.

Measurements

I-V Characteristics: Forward and reverse junction current. Leakage Current: Reverse bias leakage at various gate voltages. Breakdown Voltage: Maximum reverse voltage before breakdown. Ideality Factor: Junction quality from forward I-V. Gate-Controlled Leakage: Surface vs. bulk leakage separation.

Gate Voltage Effects

Accumulation: Gate attracts majority carriers to surface. Depletion: Gate depletes surface of carriers. Inversion: Gate inverts surface, creating channel. Leakage Modulation: Gate voltage changes surface leakage.

Applications: Junction leakage monitoring, process development, reliability testing, failure analysis, surface passivation evaluation.

Advantages: Separates surface and bulk leakage, comprehensive junction characterization, gate control for detailed analysis.

Tools: Semiconductor parameter analyzers, probe stations, automated test equipment.

Gated diode is powerful for junction analysis — by adding gate control to a simple diode, it enables detailed characterization of junction properties and leakage mechanisms critical for device performance and reliability.