Failure Mechanisms of GaN Metal–Semiconductor–Metal Photodetectors After Stressing
Print the complete model   View model as image

Model Image
Model Image
(Click on image to see full size version)

Model Parameters
Name Description Parameter Type Value Units View Sub-Model
JDark current of MSM PDsVariableampere 
A*nEffective Richardson constantConstant (Testing Req.)Not Specified 
A*pEffective Richardson constantConstant (Testing Req.)Not Specified 
Φn1Electron barrier height at the cathodeVariableNot Specified 
Φp2Hole barrier height at the anodeVariableNot Specified 
kBoltzman’s constantConstant (Physical)Not Specified 
ΔΦn1Image force lowering term at the cathodeVariableNot Specified 
ΔΦp2Image force lowering term at the anodeVariableNot Specified 

Failure Mechanism

Component / Technology Types

Title Description
Dark CurrentThe increasing dark current originates from both the barrier-height shrinkage and the crystal-quality decline.
Crystal Quality DecayThe long-duration and high-current stress causes the most crystal quality decay in GaN films.
Barrier HeightThe barrier height of the TiW/GaN interface shrinks as the stress time increases.
Model DescriptionThis model was developed from a study to address the reliability of GaN metal-semiconductor-metal (MSM) photodetectors (PDs), which is an important factor in determining the commercial success of these devices. More specifically, this study stressed GaN MSM PDs with TiW electrodes under high temperatures and high injected currents.

Title Description
ElectrodesIt is assumed that the two electrodes are symmetrical in barrier height and that surface transport can be neglected.
Simulation AccuracyTo improve the simulation accuracy, dark current is set at 15 V to guarantee that the applied voltage is greater than the flatband voltage. The dark current is presumably the result of thermionic emission at 15-V bias.

Title Description
Technology TypeThis model was developed specifically for GaN metal-semiconductor-metal (MSM) photodetectors (PDs) with TiW electrodes. TiW is considered by many to be a replacement candidate for indium tin oxide (ITO) electrodes (for UV applications), as scientific predictions indicate that indium mining will decrease sharply in the next 10 years.

Title Description
TemperatureTwo stress temperatures were used in this experiment: 298 and 373 K.
Current Stress ConditionsThree current stress conditions were used in this experiment: 5, 10, 15 mA. The critical current level of 15 mA was determined to prevent overstressing the devices.

Uncertainty Limits
Type Uncertainty

Data or Information Needed from Outside Sources
Category Source Description
Scaling FactorUserEffective Richardson's constants (A*n, A*p)

Bibliographic Citation
Published Status Source Type Title Authors
PublishedArticle/PaperFailure Mechanisms of GaN Metal–Semiconductor–Metal Photodetectors After StressingY Z Chiou
This paper proposes a new method of analyzing the reliability of GaN metal-semiconductor-metal (MSM) photodetectors (PDs). This paper analyzes and characterizes the reliability of GaN MSM PDs with TiW electrodes under different stressing conditions. Controlling the temperature and injection current makes it possible to stress the device and evaluate its characteristics after stressing. Results show that the dark current and responsivity of PDs change with the aging temperature and current. The aging current density is a dominant factor in reliability. This paper also conducts failure analysis to clarify the PD failure mechanisms. Optical microscope inspection shows that burned-fail electrodes are a major cause of failure. Photoluminance analysis shows that the decline of GaN crystal quality is another cause of failure.
Report # Publication Name Volume # Publisher Name
N/AIEEE Transactions on Device and Materials Reliability10-1N/A
Publication Date Pages Source URL Copyright Info

Technical Point of Contact (PoC)
Y Z Chiou
Personally Developed Model

If you would like to contact this person:
Please Register or Login
Model Usefulness Rating
1 for not useful and 5 for very useful.

1 2 3 4 5
Please Register or Login to rate this model.

WARP Forum Comments
Jan 9 at 11:45 am
This is the official thread for: Failure Mechanisms of GaN Metal–Semiconductor–Metal Photodetectors After Stressing
Please post your comments on the model here.

If you would like to have the ability to add comments, you must Register as a user of WARP or Login.

Add Model Validation Data
Enter published or experimental data that validates the PoF Model.


The models and references contained herein have been compiled from the open literature and government and nongovernment technical reports and are intended to be used for reference purposes only. Neither the United States Government, Wyle Laboratories nor Quanterion Solutions Incorporated warrant the applicability and accuracy of these models. The user is further cautioned that the models and references contained herein may not be used in lieu of other contractually cited references and specifications.

Publication of these models and references is not an expression of the opinion of The United States Government or Wyle Laboratories or Quanterion Solutions Incorporated as to the quality of any model mentioned herein and any use for advertising or promotional purposes of these models or references in conjunction with the name of The United States Government, or Wyle Laboratories or Quanterion Solutions Incorporated without written permission is expressly prohibited.