Design and 3D Electrical Simulations for a Controllable Equal-Gap Large-Area Silicon Drift Detector.

Area of Science:

• Semiconductor device physics
• Radiation detection technology
• Large-area silicon drift detectors (L-SDD)

Background:

• Traditional silicon drift detectors (SDDs) face challenges with widening gaps in larger designs, leading to increased invalid detector areas.
• Surface leakage current at the SiO2-Si interface is a critical factor affecting SDD performance.

Purpose of the Study:

• To design a controllable, equal-gap, large-area silicon drift detector (L-SDD) that overcomes limitations of previous designs.
• To reduce surface leakage current by minimizing the SiO2-Si interface.
• To ensure a uniform gap, regardless of detector size, thereby minimizing invalid detector areas.

Main Methods:

• A novel controllable equal-gap design was developed to reduce the SiO2-Si interface.
• A spiral hexagonal equal-gap L-SDD with a 1 cm radius was selected for design calculations.
• 3D modeling and simulation were implemented to analyze the device's electrical performance.

Main Results:

• Simulation confirmed a uniform internal potential gradient distribution, establishing a drift electric field.
• The electric field directs electron drift towards the collecting anode, indicating an excellent electron drift channel.
• Analysis of the drift channel's electrical performance validated the design methodology.

Conclusions:

• The controllable equal-gap L-SDD design effectively reduces surface leakage current and invalid detector area.
• The uniform drift electric field and excellent electron drift channel demonstrate the design's viability for advanced radiation detection.
• The proposed design method is verified as correct and suitable for large-area silicon drift detectors.