A study on the shielding mechanisms of SOI pixel detector

TL;DR

This paper investigates charge injection issues in SOI pixel detectors and demonstrates that Double-SOI shielding significantly improves effectiveness and design flexibility compared to Nested-well through experimental and simulation results.

Contribution

It introduces and compares two shielding mechanisms, Nested-well and Double-SOI, for SOI pixel detectors, highlighting the superior performance of Double-SOI.

Findings

Double-SOI provides better shielding than Nested-well.

Shielding layers are essential for counting type pixels.

Simulation shows high sheet resistance affects shielding effectiveness.

Abstract

In order to tackle the charge injection issue that had perplexed the counting type SOI pixel for years, two successive chips CPIXTEG3 and CPIXTEG3b were developed utilizing two shielding mechanisms, Nested-well and Double-SOI, in the LAPIS process. A TCAD simulation showed the shielding effectiveness influenced by the high sheet resistance of shielding layers. Test structures specially designed to measure the crosstalk associated to charge injection were implemented in CPIXTEG3/3b. Measurement results proved that using shielding layer is indispensable for counting type pixel and Double-SOI is superior to Nested-well in terms of shielding effectiveness and design flexibility.