CN-224218750-U - X-ray vertical channel field effect transistor detector

CN224218750UCN 224218750 UCN224218750 UCN 224218750UCN-224218750-U

Abstract

The utility model discloses an X-ray vertical channel field effect transistor detector which comprises an X-ray sensing part, a current modulation part and a charge coupling induction part, wherein the X-ray sensing part is formed by a high atomic number semiconductor crystal and a corresponding semiconductor structure, absorbs high-energy X-rays and generates electron/hole pairs, the current modulation part is formed by a porous source electrode, a semiconductor channel and a drain electrode, and the charge coupling induction part is formed by a grid electrode, a dielectric layer and a porous source electrode. The dielectric layer is positioned above the X-ray sensing layer. The utility model amplifies the photoelectric current by utilizing the gain of the field effect transistor to obtain high-sensitivity X-ray detection, sets the X-ray sensing layer between the grid electrode and the dielectric layer, blocks dark current by the dielectric layer, transmits incident X-ray signals to photocurrent by utilizing charge coupling induction, and obtains low-noise X-ray detection.

Inventors

LEI WEI
LI QING
ZHOU JIANMING
ZHU YING
XU XIAOBAO
WU ZHONG
ZHAO ZHIWEI

Assignees

苏州奕赫光电子科技有限公司
东南大学

Dates

Publication Date: 20260508
Application Date: 20250428

Claims (8)

1. An X-ray vertical channel field effect transistor detector is characterized by comprising an X-ray sensing part, a current modulation part and a charge coupling induction part; The X-ray sensing part is composed of a semiconductor material for absorbing X-rays and a corresponding semiconductor structure, and absorbs high-energy X-rays to generate electron/hole pairs; The current modulation part is composed of a porous source electrode, a semiconductor channel and a drain electrode, wherein the semiconductor channel is arranged between the porous source electrode and the drain electrode, and photocurrent is obtained through the semiconductor channel; The charge coupling induction part consists of a gate electrode, a dielectric layer and a porous source electrode, wherein the gate electrode is arranged below the X-ray sensing part, a passivation layer is arranged on the gate electrode, the dielectric layer is arranged above the X-ray sensing part, and the porous source electrode is arranged above the dielectric layer.
2. The vertical channel field effect transistor detector as claimed in claim 1, wherein the atomic number of the semiconductor material for X-ray absorption is not less than 30, and the mass density is not less than 3g/cm 3 .
3. An X-ray vertical channel field effect transistor detector as defined in claim 2, wherein the semiconductor junction sensing structure in the X-ray sensing section is formed by preparing a p-type top semiconductor junction layer and an n-type bottom semiconductor junction layer on a semiconductor material to form a p-i-n junction, or by simultaneously setting the top semiconductor junction layer and the bottom semiconductor junction layer to be p-type or n-type to form a p-i-p or n-i-n junction.
4. An X-ray vertical channel field effect transistor detector according to claim 3 wherein said porous source electrode is a metal electrode which is electrically grounded, holes are provided in the surface of the porous source electrode, and said drain electrode is a metal electrode.
5. The vertical channel field effect transistor detector as defined in claim 4, wherein said dielectric layer has a high dielectric property and a high dielectric constant.
6. The vertical channel X-ray field effect transistor detector as recited in claim 5, wherein said dielectric layer is a HfO 2 dielectric layer.
7. The X-ray vertical channel field effect transistor detector as recited in claim 6, wherein said passivation layer is a SiO 2 or SiN x layer.
8. An X-ray vertical channel field effect transistor detector as defined in claim 7 wherein said semiconductor channel is a ZnO layer.

Description

X-ray vertical channel field effect transistor detector Technical Field The utility model relates to the field of photoelectric detection, in particular to an X-ray detection technology. Background Because of the high energy of X-ray photons, which has a strong penetration into target objects, X-ray imaging is widely used in medical and industrial manufacturing to achieve non-destructive testing of disease and industrial products. Generally, there are two ways of X-ray detection, direct detection and indirect detection, as shown in fig. 1a and 1 b. In the direct detection process, the semiconductor layer absorbs incident X-ray energy and is converted into electron/hole pairs. These photo-generated electron/hole pairs are separated by the electric field and drift to form a detection electrical signal. In the X-ray indirect detection process, X-ray photons firstly enter a scintillator to excite visible fluorescence, and then a semiconductor detector is used for detecting visible fluorescence signals. Compared with an X-ray indirect detector, the X-ray direct detector does not need the process of converting X-rays into visible fluorescence, so that the X-ray direct detector can have higher external quantum efficiency. Furthermore, the X-ray direct detector avoids scattering of visible fluorescence, so that it can also have a higher imaging spatial resolution. However, in the case of an X-ray direct detector, the absorption semiconductor is required to be relatively thick (mm) in order to sufficiently absorb and convert high-energy X-ray photons. In order for the electrons and holes generated by the absorbing semiconductor to be completely separated and drift to form an electrical signal, a high bias voltage (hundreds of volts) is required to be applied across the direct detector. If a high bias voltage is applied across the X-ray direct detector shown in fig. 1a, the dark current of the detector, as well as the noise created by current fluctuations, will generally be relatively large. Thus, in a conventional X-ray direct detector, the detection sensitivity of the X-rays (proportional to the photocurrent) and the signal-to-noise ratio (inversely proportional to the noise signal) are mutually constrained. How to obtain high-sensitivity low-noise X-ray detection is an urgent problem to be solved. Disclosure of utility model Aiming at the problems of the conventional X-ray direct detector, the utility model provides an X-ray vertical channel field effect transistor detector which amplifies the photoelectric current by utilizing the gain of a field effect transistor to obtain high-sensitivity X-ray detection, an X-ray sensing layer is arranged between a grid electrode and a dielectric layer, dark current is blocked by the dielectric layer, and an incident X-ray signal is transmitted to photocurrent by utilizing charge coupling induction to obtain low-noise X-ray detection. The technical scheme adopted by the utility model is that the X-ray vertical channel field effect transistor detector comprises an X-ray sensing part, a current modulation part and a charge coupling induction part; The X-ray sensing part is composed of a semiconductor material for absorbing X-rays and a corresponding semiconductor structure, and absorbs high-energy X-rays to generate electron/hole pairs; The current modulation part is composed of a porous source electrode, a semiconductor channel and a drain electrode, wherein the semiconductor channel is arranged between the porous source electrode and the drain electrode, and photocurrent is obtained through the semiconductor channel; When the X-ray irradiates the sensing area, the potential barrier between the source electrode and the semiconductor channel is reduced and thinned due to charge coupling induction, so that a large amount of electrons are injected into the semiconductor channel from the source electrode to form photocurrent; The charge coupling induction part consists of a gate electrode, a dielectric layer and a porous source electrode, wherein the gate electrode is arranged below the X-ray sensing part, a passivation layer is arranged on the gate electrode, the dielectric layer is arranged above the X-ray sensing part, and the porous source electrode is arranged above the dielectric layer. The photo-generated holes generated by the X-ray sensing layer are blocked by the dielectric layer and accumulated below the dielectric layer. Electrons of equal charge amounts will be induced on the dielectric layer near the Fang Duokong source electrode according to the charge-induced coupling effect. The large number of electrons induced near the porous source electrode can reduce the potential barrier between the source electrode and the semiconductor channel, so that electrons are injected into the semiconductor channel from the porous source electrode. Further, the atomic number of the semiconductor material for absorbing X-rays is more than or equal to 30, and the mass density is more t