Active Edge Silicon Sensors Fabricated With Edge Ion Implantation and Microwave Annealing for Dopant Activation

TL;DR

This paper introduces a simplified fabrication process for active edge silicon sensors using side ion implantation and microwave annealing, reducing insensitive regions and improving edge leakage current performance.

Contribution

The authors develop a new, less complex method for fabricating highly doped edges in silicon sensors, enhancing performance and reducing costs.

Findings

Significant reduction in edge leakage current after processing.

Successful demonstration of the proposed fabrication technique.

TCAD simulations support experimental results.

Abstract

Silicon detectors typically require an insensitive area around their periphery to accommodate guard rings, which help maintain the electric field uniformity around edge pixels and isolate the high leakage current from the physical edges of the detector. Minimization of this insensitive region is desirable for applications in high-energy physics, X-ray experiments, and medical imaging. Existing active edge technology offers a solution for reduction or total elimination of the insensitive region, via a continuation of the highly doped backside up the sidewalls of the device. However, current methods for realizing this technology are complex and expensive. We propose a new technique that simplifies the fabrication of highly doped edges using side ion implantation and microwave annealing. Tests demonstrating the feasibility of this proposed process were performed on a set of sensors, and current versus bias voltage measurements probing the edge effects were performed before and after the edge implantation and annealing. To aid in interpretation of the results, TCAD simulations of the test devices were performed. Significant improvement in the edge leakage current is observed, indicating the promise of this simplified process for fabrication of active edge sensors.