Characterisation of a pixel sensor in SOI technology for charged particle tracking

Abstract

This paper presents the results of the characterisation of a pixel sensor manufactured OKI 0.2 µm SOI technology integrated on a high-resistivity substrate, and featuring several pixel cell layouts for charge collection optimisation. The sensor is tested with short IR laser pulses, X-rays and 200 GeV pions. We report results on charge collection, particle detection efficiency and single point resolution.

Characterisation of a thin fully depleted SOI pixel sensor with high momentum charged particles

“…Since the determination of the effective area used to derive the capacitance is affected by a large uncertainty, we use the C − V measurement only for establishing the voltage at which the sensor is fully depleted. From the evolution of the capacitance with the depletion voltage, we estimate that the detector is fully depleted for V d > 40 V. This is in agreement with what expected from the results of the 2010 beam test [2] and the resistivity deduced from the SRA analysis [6].…”

“…A grid of p-type guard-rings surrounds the I/O electronics at the chip periphery, while an external guard-ring surrounds the entire sensor design. This sensor has already been successfully tested with high momentum particles at the CERN SPS in 2010 [2]. The sensor under test is back-thinned using a commercial grinding technique [4] which has been already successfully employed for back-thinning CMOS Active Pixel Sensors [5].…”

“…The thinned SOI chip has been placed upstream from a doublet made of the same SOI chips with full thickness. The doublet was already used in the 2010 beam test data taking [2]. The setup has been exposed to a 300 GeV π − beam.…”

“…Silicon on Insulator (SOI) is one of the leading technologies for manufacturing these devices with the possibility of integrating advanced data processing capabilities. With the mitigation of the back-gating effect by implanting a buried p-well (BPW) beneath the buried oxide (BOX) [1], SOI pixel sensor prototypes have demonstrated high detection efficiency and micron-size single point resolution [2]. Because of the need to minimise multiple scattering in precision vertex tracking at future colliders, the total thickness of sensor ladders should be ≤ 100 µm of Si-equivalent while retaining high S/N and detection efficiency [3].…”

CMOS monolithic active pixel sensors for high energy physics

“…One impressive development [22] demonstrated good performance in a particle beam [23]. Further work is planned to improve the radiation tolerance, lower due to accumulation of radiation induced charge in the buried oxide.…”