Gallium Nitride (GaN) Diode Characterization

Advanced Gallium Nitride (GaN) Diode Characterization – Comprehensive Testing Services for Power and RF Applications

Gallium nitride (GaN) diodes – including Schottky barrier diodes (SBDs), p‑i‑n diodes, and junction barrier Schottky (JBS) rectifiers – have emerged as pivotal components in high‑efficiency power converters, electric vehicle drivetrains, renewable energy inverters, and RF front‑end modules. Their wide bandgap, high critical electric field, and superior electron mobility enable lower on‑resistance, faster switching, and higher operating temperatures compared to silicon counterparts. However, the performance and reliability of GaN diodes are critically dependent on material quality, junction design, and packaging integrity. Clients seeking GaN diode testing services typically aim to: (i) verify forward and reverse characteristics against datasheet specifications, (ii) evaluate Breakdown Voltage and avalanche ruggedness, (iii) characterize switching dynamics and reverse recovery behavior, (iv) assess thermal impedance and reliability under accelerated stress, and (v) perform failure analysis to identify root causes of parametric drift or catastrophic failure. Our laboratory offers a fully integrated, ISO/IEC 17025‑accredited GaN diode testing service that combines DC and pulsed I‑V, high‑voltage breakdown, capacitance‑voltage (C‑V), switching characterization, thermal analysis, and reliability testing into a unified assessment platform. We go beyond standard pass/fail testing to deliver a predictive performance and reliability fingerprint that correlates material properties, device architecture, and operational conditions with long‑term stability, enabling our clients to optimize design, improve yield, and accelerate time‑to‑market.

DC and Pulsed Current‑Voltage Characterization – Static Performance and Self‑Heating Separation

Fundamental to any GaN diode evaluation is the accurate measurement of forward and reverse characteristics. Our testing platform comprises a high‑voltage semiconductor parameter analyzer (Keysight B1505A) with high‑power source‑measure units (up to 1500 V and 50 A) and a temperature‑controlled probe station (Cascade Summit 12000) covering –60 °C to +300 °C. We perform forward I‑V measurements to extract the turn‑on voltage (V_F), on‑resistance (R_ON), and ideality factor, and reverse I‑V to determine Leakage Current and Breakdown Voltage (V_BR). To separate self‑heating effects from intrinsic device response, we perform pulsed I‑V measurements with pulse widths from 200 ns to 10 µs and duty cycles as low as 0.01%, using a high‑speed pulse generator and a digitizing oscilloscope synchronized with the SMUs. This allows us to extract the isothermal I‑V characteristics and quantify the thermal resistance (R_th) from the difference between DC and pulsed curves. We also measure the temperature dependence of V_F and R_ON from –60 °C to +200 °C, providing the temperature coefficients essential for thermal compensation and lifetime modeling.

Breakdown Voltage and Avalanche Capability Assessment

The Breakdown Voltage and avalanche ruggedness of GaN diodes are critical for power applications, where transient overvoltages and inductive load switching can subject the device to high‑energy stress. Our high‑voltage test setup can apply up to 1500 V (or higher upon request) in both DC and pulsed modes, measuring the reverse Leakage Current with a resolution of 1 pA. We determine the Breakdown Voltage (V_BR) at a defined leakage criterion (e.g., 1 mA/cm²) and evaluate its temperature coefficient (positive or negative), which indicates the dominant breakdown mechanism (avalanche or Zener). For avalanche capability, we perform unclamped inductive switching (UIS) tests, applying a defined inductive load and measuring the peak avalanche current and energy until device failure. This provides the avalanche energy rating (E_AS) and the avalanche current (I_AR), essential for designing robust power circuits. We also measure dynamic Breakdown Voltage under fast voltage ramps (dV/dt up to 100 V/ns) to assess the device’s ability to withstand high‑speed transients without premature breakdown.

Capacitance‑Voltage and Trapping Analysis – Interface and Bulk Defect Characterization

Trapping effects are a major reliability concern in GaN diodes, causing dynamic on‑resistance increase, threshold voltage instability, and Leakage Current drift. We perform capacitance‑voltage (C‑V) measurements (1 kHz to 10 MHz) on Schottky and p‑i‑n diodes to extract the carrier concentration profile, built‑in potential, and interface trap density (D_it) using the Terman and conductance methods. For deeper trap characterization, we employ deep‑level transient spectroscopy (DLTS) with a temperature range of 77 K to 500 K and a filling pulse width from 1 µs to 100 ms. We identify the activation energy (E_a), capture cross‑section, and trap concentration of each defect level, correlating them with known trap signatures (e.g., carbon‑related, nitrogen‑vacancy, or Fe‑related). We also perform isothermal transient spectroscopy (ITS) to study trapping dynamics under real‑time bias conditions. Our advanced analysis includes the Laplace DLTS technique for resolving closely spaced trap levels, providing a comprehensive trap inventory that is essential for reliability prediction. We complement this with frequency‑dependent conductance measurements to separate surface state contributions from bulk traps.

Switching Characteristics and Reverse Recovery – Dynamic Performance Evaluation

For power conversion applications, the switching speed and reverse recovery behavior of GaN diodes directly affect converter efficiency and electromagnetic interference. Our laboratory offers a comprehensive dynamic characterization suite using a custom‑built double‑pulse tester with a high‑bandwidth oscilloscope (1 GHz) and high‑voltage probes. We measure the reverse recovery time (t_rr), reverse recovery charge (Q_rr), and softness factor under various forward currents, reverse voltages, and dI/dt conditions (up to 1000 A/µs). For GaN SBDs, which are majority‑carrier devices, the reverse recovery is typically negligible, but we still verify this and quantify any capacitive charge. We also measure the junction capacitance (C_J) and its voltage dependence, which affects switching losses. For p‑i‑n diodes, we evaluate the stored charge and its temperature dependence. Additionally, we assess dynamic on‑resistance (R_ON,dyn) by applying a high‑voltage off‑state stress followed by a fast turn‑on pulse, revealing any trapping‑induced increase in R_ON – a critical reliability metric for GaN power devices.

Thermal Characterization and Reliability Testing – Junction Temperature and Lifetime Prediction

The self‑heating effect in GaN diodes is significant due to high power density and the relatively low thermal conductivity of GaN and its substrates. We perform thermal resistance (R_th) measurement using the transient thermal impedance method (T3Ster® system), which applies a step current and records the cooling curve of the forward voltage to derive the structure function and the cumulative thermal resistance network (junction‑to‑case, case‑to‑ambient). We also employ infrared (IR) thermography with a spatial resolution of 5 µm to map the temperature distribution across the active area under actual bias, identifying hot spots that may lead to local degradation. For reliability, we operate a dedicated multi‑site stress system capable of applying constant current, constant voltage, or pulsed stress to up to 96 devices simultaneously, with independent temperature control (up to 300 °C) and humidity (10‑95% RH). We perform the following accelerated stress tests:

(i) High‑temperature reverse bias (HTRB) – to evaluate the stability of the drift region and the passivation.

(ii) High‑temperature forward bias (HTFB) – to assess contact degradation and dopant diffusion.

(iii) Power cycling with a typical on‑time of 1‑5 minutes and off‑time of 1‑2 minutes to simulate application conditions.

(iv) Humidity‑temperature‑bias (HTB) (85 °C/85% RH) with bias to evaluate electrochemical corrosion.

(v) ESD (HBM and CDM) per ANSI/ESDA/JEDEC standards to assess robustness.

During stress, we periodically measure DC and switching parameters to monitor degradation. We analyze the degradation kinetics using Arrhenius, Eyring, and power‑law models, extracting the activation energy (E_a) and the lifetime (L₁₀, L₅₀) at use conditions. Our proprietary physics‑of‑failure (PoF) framework combines experimental data with TCAD simulations to identify the dominant failure mechanisms (e.g., contact spiking, defect generation, or passivation degradation) and to provide guidelines for derating or design improvement.

Failure Analysis – From Electrical Faults to Physical Root Causes

When GaN diodes fail to meet specifications or exhibit unexpected degradation, our failure analysis (FA) service provides a systematic, multi‑technique investigation. Our FA flow includes:

(i) Electrical characterization to confirm the failure mode (e.g., increased leakage, open circuit, degraded V_F).

(ii) Optical inspection to detect visible damage (burn marks, cracks, discoloration).

(iii) Scanning electron microscopy (SEM) with EDS for imaging and elemental analysis of the contact pads, field plates, and passivation layers.

(iv) Focused ion beam (FIB) cross‑sectioning followed by TEM to examine the Schottky interface, the p‑n junction, and the substrate‑epitaxy interface at the atomic scale, revealing dislocation clusters, metal diffusion, or void formation.

(v) Scanning probe techniques (AFM, KPFM) to map surface potential and workfunction changes.

(vi) Electroluminescence (EL) and photoluminescence (PL) imaging to locate non‑radiative regions or current crowding.

We combine these data to reconstruct the failure timeline and determine the root cause – whether it is process‑induced (e.g., Schottky barrier inhomogeneity), material‑related (e.g., dislocations), or application‑driven (e.g., overstress). Our reports include a clear conclusion and recommended corrective actions, such as changing the passivation dielectric, adjusting the field plate design, or modifying the ohmic contact annealing.

Our Distinctive Competencies – Integration, Physics‑Based Insight, and Global Traceability

What sets our GaN diode testing service apart is the seamless integration of electrical, thermal, and physical characterization within a single laboratory, combined with a strong foundation in GaN device physics. Our team comprises PhD‑level researchers and engineers with extensive experience in GaN diodes, including design, fabrication, and modeling. We do not simply report numbers; we interpret them in terms of underlying mechanisms – for example, distinguishing between trap‑related dynamic R_ON and thermal‑related degradation, or differentiating between interface roughness scattering and alloy disorder scattering in mobility reduction.

Our laboratory is ISO/IEC 17025 accredited for many of the test methods (I‑V, C‑V, switching, HTRB, HTGB), and we maintain NIST‑traceable calibrations for all equipment. We participate in international round‑robins (e.g., JEDEC JC‑70, IEEE PELS) to ensure our measurement procedures and data are comparable with leading labs worldwide. We offer rapid turnaround (3‑5 business days for standard DC and switching tests, 2‑3 weeks for reliability tests) and flexible sample handling, accepting bare die, packaged devices, or full wafers (up to 200 mm).

We also provide custom test development for emerging GaN diode architectures (e.g., vertical GaN SBDs, JBS, or trench MOS) and for non‑standard operating conditions (e.g., cryogenic temperatures, high‑voltage pulse trains). Our data analytics platform employs machine learning to identify subtle correlations between process parameters and device characteristics, helping clients accelerate process optimization and yield improvement.

Comprehensive Service Modules – Tailored to Your Diode Type and Lifecycle

We structure our testing into modular packages to meet diverse client needs:

Module 1 – Basic DC and Pulsed I‑V Characterization: Forward voltage, on‑resistance, reverse leakage, Breakdown Voltage, and temperature coefficients – essential for parameter extraction and initial device sorting.

Module 2 – Breakdown and Avalanche Ruggedness: High‑voltage breakdown, UIS testing, and dynamic breakdown – for power device qualification.

Module 3 – Trapping and Interface Characterization: C‑V (D_it, carrier profile), DLTS (trap energy, capture cross‑section), and conductance method – for trapping analysis and reliability prediction.

Module 4 – Switching and Reverse Recovery: t_rr, Q_rr, softness factor, and dynamic R_ON – for converter efficiency and EMI assessment.

Module 5 – Thermal Characterization: R_th measurement, IR thermography, and thermal impedance spectroscopy – for thermal management validation.

Module 6 – Reliability and Lifetime Testing: HTRB, HTFB, HAST, power cycling, ESD, and Weibull/Arrhenius analysis – for qualification and lifetime prediction.

Module 7 – Failure Analysis and Root‑Cause Investigation: SEM/EDS, FIB‑TEM, EL/PL imaging, KPFM, and comprehensive forensic reporting – for return analysis and process improvement.

Module 8 – Comprehensive Diode Qualification Package: All modules combined into a single project, with integrated correlation analysis, statistical summary, and a detailed interpretive report – suitable for product release, customer audits, or regulatory submissions.

We also offer custom test plans for special requirements, such as radiation hardness evaluation, TID (total ionizing dose) testing, or high‑temperature gate‑switching tests.

Data Integrity, Security, and Reporting

All measurements are performed under strict SOPs, with fully traceable calibration records and environmental logging. Our Laboratory Information Management System (LIMS) records every operation, operator, and timestamp, ensuring full auditability. We use encrypted data transfer and role‑based access to protect client proprietary information. Our reports include comprehensive tables, 2D/3D graphs, uncertainty budgets, and an executive summary that translates technical findings into actionable business insights. We provide raw data files (CSV, Excel) upon request. A post‑delivery review meeting is included to discuss results and recommend next steps.

Client Engagement and Workflow

Our engagement begins with a complimentary consultation to define your diode type, application, critical parameters, and any specific concerns (e.g., dynamic R_ON, avalanche failure, or thermal runaway). We then propose a tailored test plan with a fixed price and timeline. Upon sample receipt (we accept die, packages, or wafers), we log and inspect the samples, then commence testing. Clients receive progressive updates through our secure portal, with preliminary data shared on request. The final report is delivered in PDF format, and we offer a follow‑up call to discuss the findings and their implications for your development or production.

Conclusion – Empowering Your GaN Diode Technology with Unrivaled Testing Excellence

GaN diodes represent a paradigm shift in power conversion and RF electronics, but their full potential can only be realized through rigorous, multidimensional, and physics‑based characterization across all stages of development, from epitaxy to packaging. Our comprehensive testing service provides exactly that – a one‑stop, ISO‑accredited solution that delivers not only accurate measurements but also deep insights into device behavior, degradation mechanisms, and reliability margins. With our advanced instrumentation, experienced scientific team, and unwavering commitment to quality, we enable our clients to accelerate innovation, reduce risk, and confidently bring high‑performance GaN diodes to market.

We invite you to contact our GaN diode testing specialists to discuss your specific needs. Let us partner with you to ensure that your GaN SBDs, p‑i‑n diodes, and JBS rectifiers achieve the highest standards of performance, robustness, and longevity – from the first prototype to high‑volume production. Your journey to GaN diode excellence starts with our rigorous, integrative, and actionable testing.