Measurement of Switching Performance of Pixelated Silicon Sensor Integrated with Field Effect Transistor.

Hyeyoung Lee,Manwoo Lee,Sukjune Song,Jin-A Jeon,Jinyong Kim,Seungcheol Lee,Moo Hyun Lee,Hyunsu Lee,Hwanbae Park

doi:10.3390/s19245580

Abstract

Silicon shows very high detection efficiency for low-energy photons, and the silicon pixel sensor provides high spatial resolution. Pixelated silicon sensors facilitate the direct detection of low-energy X-ray radiation. In this study, we developed junction field effect transistors (JFETs) that can be integrated into a pixelated silicon sensor to effectively handle many signal readout channels due to the pixelated structure without any change in the sensor resolution; this capability of the integrated system arises from the pixelated structure of the sensor. We focused on optimizing the JFET’s switching function, and simulated JFETs with different fabrication parameters. Furthermore, prototype JFET switches were designed and fabricated on the basis of the simulated results. It is important not only to keep the low leakage currents in the JFET but also reduce the current flow as much as possible by providing a high resistance when the JFET switch is off. We determined the optimal fabrication conditions for the effective switching of the JFETs. In this paper, we present the results of the measurement of the switching capability of the fabricated JFETs for various design variables and fabrication conditions.

Highlights

This paper presents junction field effect transistors (JFETs) that can be used as switches after integration into a pixelated silicon sensor used for the direct detection of low-energy X-ray radiation in protein crystallography
The fabrication of the rear side of the sensor can affect the front side, where the JFET is located, and we did not fabricate the rear side, especially since this study focused on the performance of the JFET’s switching capability
Since it is important to minimize the current flow in the off state of the JFET by providing a high resistance, we simulated, designed, and fabricated different versions of the JFET

Summary

Introduction

This paper presents junction field effect transistors (JFETs) that can be used as switches after integration into a pixelated silicon sensor used for the direct detection of low-energy X-ray radiation in protein crystallography. When an appropriate reverse bias voltage is applied to a gate control pad, all JFET switches (gates) on the line are turned on and charges from their drains are transferred to the readout pad through the vertical read lines. Since it is important to minimize the current flow in the off state of the JFET by providing a high resistance, we simulated, designed, and fabricated different versions of the JFET by varying the doping levels of the device regions, the sizes, and the distances between each of the terminals. The JFETs were tested to ascertain the effects of each variable on the switching and we present the test results in this paper

Simulation

Fabrication

Performance Measurement

Conclusions

Methods