Development of a pixel sensor with fine space-time resolution based on SOI technology for the ILC vertex detector

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Abstract

We have been developing a new monolithic pixel sensor with silicon-on-insulator (SOI) technology for the International Linear Collider (ILC) vertex detector system. The SOI monolithic pixel detector is realized using standard CMOS circuits fabricated on a fully depleted sensor layer. The new SOI sensor SOFIST can store both the position and timing information of charged particles in each 20×20 μm2 pixel. The position resolution is further improved by the position weighted with the charges spread to multiple pixels. The pixel also records the hit timing with an embedded time-stamp circuit. The sensor chip has column-parallel analog-to-digital conversion (ADC) circuits and zero-suppression logic for high-speed data readout. We are designing and evaluating some prototype sensor chips for optimizing and minimizing the pixel circuit.

Introduction

Silicon-on-insulator (SOI) wafer technology can be used to achieve a monolithic pixel detector [1], which integrates both a semiconductor pixel sensor and readout electronics in the same silicon wafer (Fig. 1). The SOI wafer has a multi-layer structure in which a low-resistivity Si layer for the CMOS circuit is bonded to a high-resistivity handle-wafer layer. The middle oxide layer called buried oxide (BOX) insulates these two layers. The SOI pixel sensor is realized by adopting a bottom layer as the depleted Si sensor.

The SOI pixel sensor has the following advantages compared with conventional hybrid detectors:

  • Low material budget owing to the monolithic detector structure.

  • Smaller pixels with non-mechanical bump-bonding.

  • Implementation of complex functions in a pixel with a standard CMOS circuit process.

  • Large conversion gain and low noise because of low parasitic capacitance.

In addition, we have been developing a pixel sensor with a double-SOI wafer. A double-SOI wafer has an additional middle Si layer in the BOX layer. This middle Si layer can compensate the effect caused by the accumulation of holes in the oxide layer [2], [3]. The double-SOI pixel sensor has higher radiation tolerance for total ionization dose (TID) damage.

The SOI pixel sensor is suitable for application in high energy physics experiments. We are studying an SOI pixel sensor optimized for the vertex detector system of the International Linear Collider (ILC) experiment. The physics goals at the ILC are the precise measurement of the Higgs bosson and the search for new particles [4]. The ILC requires the detector system to achieve precise vertex measurement for generated particles. The ILC vertex detector system is required to be developed using a new pixel sensor with higher position resolution, fine time resolution, and fast readout speed. We are currently developing a new SOI pixel sensor, the SOi sensor for FIne measurement of Space and Time (SOFIST), with fine position and time resolutions.

In this paper, we report the development status of the prototype sensor chips for the SOFIST pixel circuit integration.

Section snippets

SOFIST overview: SOI pixel sensor optimized for ILC

The goal of SOFIST is to function as the innermost and second layers of the ILC vertex detector system. We have the following target performances and functions for the SOFIST development:

  • 1.

    Single point resolution: We are designing a pixel circuit with a pitch less than 25 μm to achieve a detector vertex resolution of 5 μm [5]. The sensor resolution will be improved further by the weighted position of the charges spread to multiple pixels. The target of single point resolution is better than 3 μm.

Development of prototype sensor chips

The technical issue of SOFIST development is the layout size of the pixel circuit. In order to install all functions in a 20×20 μm2 pixel, we have to optimize the layout size of each circuit. The plan of the prototype sensor development for evaluating the pixel circuit is as follows. We will also test the ADC and digital logic circuits for pixel signal readout with these prototype sensors.

  • Ver.1: Pixel with analog signal readout and column-ADC.

  • Ver.2: Pixel with time-stamp and zero-suppression

Summary and future prospect

A pixel sensor with fine position and time resolution is required for the ILC vertex detector. We have been developing a monolithic pixel sensor SOFIST based on SOI technology. SOFIST stores both the position and timing information of charged particles. We are currently designing and evaluating 2 prototype sensor chips. SOFIST Ver.1 chip has a pixel circuit with analog signal readout and Ver.2 chip has pixels with the time-stamp function. After the evaluation of the basic performances, we will

Acknowledgement

This work was supported by MEXT KAKENHI Grant-in-Aid for Scientific Research on Innovative Areas 25109001, and also by the VLSI Design and Education Center (VDEC), The University of Tokyo, with the collaboration of Cadence Design Systems, Inc., Mentor Graphics Co., Ltd., and Synopsys, Inc.

References (8)

  • Y. Arai et al.

    Developments of SOI monolithic pixel detectors

    Nucl. Instrum. Methods Phys. Res. Sect. A: Accel. Spectrom. Detect. Assoc. Equip.

    (2010)
  • K. Hara, M. Asano, S. Honda, N. Tobita, Y. Arai, I. Kurachi, S. Mitsui, T. Miyoshi, T. Tsuboyama, Initial...
  • S. Honda, et al., Total ionization damage compensations in double siliconon-insulator pixel sensors, PoS TIPP2014...
  • T. Behnke, et al., The International Linear Collider Technical Design Report Volume 1: Physics,...
There are more references available in the full text version of this article.

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