Photon Factory Activity Report 2014 #32 (2015) B

BL-14A,BL-14B/2013G708

Development of next-generation X-ray pixel sensor using SOI technology
Toshinobu Miyoshi1,*, Ryutaro Nishimura2 and Shingo Mitsui3
1
KEK-IPNS, Tsukuba 305-0801, Japan
2
SOKENDAI, Tsukuba 305-0801, Japan
3
Kanazawa Univ., Kanazawa, 920-1192, Japan
1 Introduction
The SOIPIX group is developing monolithic pixelsensors using SOI technology. The development project
has started as an important subject in KEK Developmentand Technology Project (KEK-DTP). The sensors wereevaluated with monochromatic X-rays at KEK-PFbeamlines, PF BL-14A and BL-14B. This document
describes a part of the experimental results.

in BL14A we measured sensor gain of integration-type
SOI sensor, INTPIXh2, fabricated with N-type
Czochralski (NCZ), NFZ, and double SOI wafer. We
realized the sensor gain was low in double SOI sensor
and therefore we will modify the pixel structure andcircuit to optimize the sensor. For example, anotherimplantation structure between pixels might be required
to increase charge collection efficiency.

2 Experiment
The experiment was done in 2 beamlines in FY2014.
The summary is shown in Table 1. In PF BL-14A, a wide
range of X-ray energy is available for various X-ray
detector tests and therefore it was used for full depletion
voltage, sensor gain, and quantum efficiency (QE)
measurement. In BL-14B, a large-area and uniform
beams in medium X-ray energy (10-20 keV) is available
and so it was used for tests of the phase- and absorptioncontrast imaging.
Table 1: Experiment summary
Beam
Beam time
Beamline
EnergySubjects[year/month]
[keV]
14B
2014/1216
Imaging
14A2014/1216
QE
3 SOI Pixel Sensors
SOI image sensors were developed in multi-project
wafer (MPW) runs in every year. Various LSI designs
were gathered in a common process mask. Therefore,various SOI image sensors have been used in several
beam times since 2009 [1-5]. In FY2014, Wafer quality
was improved and an integration-type pixel sensor,
INTPIX4, with 500 m-thick and N-type Float Zone(NFZ) wafer can be used under fully depleted condition.
So we demonstrated X-ray phase-contrast and absorption
imaging with medium X-ray energy in BL14B. We
obtained clear X-ray phase-contrast images of 80 mbumps with X-ray energy, 16 keV, as shown in Fig.1. The
image can be obtained within reasonable net irradiation
time, 200 msec (1msec/frame x 200 frames). We are also
developing double SOI sensors. The wafer has two SOIlayers. Top SOI layer was used for SOI-CMOS circuit,and the middle SOI layer was used as a shield to the backgate effect and the sensor-circuit cross talk. We cancontrol the potential of middle SOI layer and it cancompensate total ionization dose (TID) effect by highradiation dose. By using 16 keV monochromatic X-rays

Fig. 1: A example of phase-contrast images of 80 mbump measured by INTPIX4.
4 Future plan
In FY2015, we will continue the SOI studies. Integrationtype pixel sensors with dual storage capacitors andcounting-type pixel sensors with double SOI and p-type
wafer will be fabricated. Those sensors will be tested anddemonstrated with monochromatic X-ray.
References[1] T. Miyoshi et al., Nucl. Instr. And Meth. A, Vol. 636,Issue 1, Supplement 1, Pages S237-S241 (2011).
[2] T. Miyoshi et al., Physics Procedia, Vol.37, 1039-1045(2012).
[3] T. Miyoshi et al., Nucl. Instr. And Meth. A, Vol. 732,pages 530-534 (2013).
[4] T. Miyoshi et al., JINST 9 C05044 (2014).
[5] T. Miyoshi et al., PoS (2014): 044.
* tmiyoshi@post.kek.jp