Use of High-Field Electron Injection into Dielectrics to Enhance Functional Capabilities of Radiation MOS Sensors

Dmitrii V Andreev,Vladimir V Andreev,Gennady G Bondarenko,Alexander A Stolyarov

doi:10.3390/s20082382

Abstract

The paper suggests a design of radiation sensors based on metal-oxide-semiconductor (MOS) structures and p-channel radiation sensitive field effect transistors (RADFET) which are capable to function under conditions of high-field tunnel injection of electrons into the dielectric. We demonstrate that under these conditions, the dose sensitivity of the sensor can be significantly raised, and, besides, the intensity of radiation can be monitored in situ on the basis of determining the ionization current arising in the dielectric film. The paper proposes the model allowing to make a quantitative analysis of charge effects taking place in the radiation MOS sensors under concurrent influence of ionization radiation and high-field tunnel injection of electrons. Use of the model allows to properly interpret results of the radiation control. In order to test the designed sensors experimentally, we have utilized γ-rays, α-particle radiation, and proton beams. We have acquired experimental results verifying the enhancement of function capabilities of the radiation MOS sensors when these have been under high-field injection of electrons into the dielectric.

Highlights

Nowadays in the field of medicine, space devices, nuclear power, etc., metal-oxide-semiconductor (MOS) sensors of a radiation are widely utilized [1,2,3,4,5,6,7,8,9,10,11,12,13,14,15]
That is appropriate to use the high-field injection mode at low values of the dose range for cases when it is essential to obtain maximum dose sensitivity of the sensor as, for example, it is necessary for medical applications
We have demonstrated that under the mode of flowing of constant current through the dielectric, the initiation of ionization current, when radiation has been presented, has resulted in lowering of injection and/or capacitive current flowing through the dielectric and that, in turn, has caused the changing of time dependence of voltage across MOS structure

Summary

Introduction

Nowadays in the field of medicine, space devices, nuclear power, etc., metal-oxide-semiconductor (MOS) sensors of a radiation are widely utilized [1,2,3,4,5,6,7,8,9,10,11,12,13,14,15] Most frequently, these sensors are based on p-channel MOSFET (radiation sensitive field effect transistors (RADFET) sensors). Electric field in the dielectric film, caused by the applied voltage, initiates separation of charges, generated by radiation ionization, and increases yield of holes which avoided recombination. These holes travel to the interface with silicon where a fraction of these become trapped resulting in threshold voltage shift [1,9,13]. This specifies by possibility of arising of degradation processes influencing onto precision and efficiency of the sensors and, besides, by difficulties of maintaining

Methods

Results

Conclusion