J. Marczewski

Silicon ultra fast cameras for electron and γ sources in medical applications

Abstract SUCIMA (Silicon Ultra fast Cameras for electron and γ sources In Medical Applications) is a project approved by the European Commission with the primary goal of developing a real time dosimeter based on direct detection in a Silicon substrate. The main applications, the detector characteristics and technologies and the data acquisition system are described.

Temperature enhancement of terahertz responsivity of plasma field effect transistors

Temperature dependence of THz detection by field effect transistors was investigated in a wide range of temperatures from 275 K down to 5 K. The important increase of the photoresponse following 1/T functional dependence was observed when cooling from room temperature down to 30 K. At the temperatures below ∼30 K, the THz response saturated and stayed temperature independent. Similar behavior was observed for GaAs, GaN, and Si based field effect transistors. The high temperature data were successfully interpreted using recent theory of overdamped plasma excitation in field effect transistors. The low temperature saturation of the photoresponse was tentatively explained by the change of the transport regime from diffusive to ballistic or traps governed one. Our results clearly show that THz detectors based on field effect transistors may improve their responsivity with lowering temperature but in the lowest temperatures (below ∼30 K) further improvement is hindered by the physics of the electron transport ...

Hybrid active pixel sensors and SOI inspired option

Abstract Two novel pixel sensor concepts for future linear collider applications are presented in this paper: a hybrid pixel sensor characterized by a layout improving the single point resolution and a monolithic detector inspired by silicon on insulator (SOI) technology. The results of charge collection studies for the first prototypes of hybrid pixel sensors with interleaved pixels are reported and the new detector test structures are introduced. The technology and the readout architecture design for SOI sensors are also discussed.

Improvement of terahertz field effect transistor detectors by substrate thinning and radiation losses reduction

Phenomena of the radiation coupling to the field effect transistors based terahertz (THz) detectors are studied. We show that in the case of planar metal antennas a significant portion of incoming radiation, instead of being coupled to the transistors, is coupled to an antenna substrate leading to responsivity losses and/or cross-talk effects in the field effect based THz detector arrays. Experimental and theoretical investigations of the responsivity versus substrate thickness are performed. They clearly show how to minimize the losses by the detector/ array substrate thinning. In conclusion simple quantitative rules of losses minimization by choosing a proper substrate thickness of field effect transistor THz detectors are presented for common materials (Si, GaAs, InP, GaN) used in semiconductor technologies.

Time-Modulated Reconfigurable Antenna Based on Integrated S-PIN Diodes for mm-Wave Communication Systems

This paper concerns the study of the mm-wave reconfigurable antennas based on S-PIN diodes suitable for using in mm-wave communication systems. The investigated antennas were designed, fabricated, and subjected to the measurements in both steady and transient states. One selected antenna was incorporated into a wireless system to determine its suitability for operating in such a system as a time-modulated linear array. By means of appropriate switching of the antenna, multiple radio frequency (RF) chains were simulated in a receiver having only one RF chain. This allowed applying a combining technique for improving the system performance in a presence of a strong interfering signal.

Silicon junctionless field effect transistors as room temperature terahertz detectors

Terahertz (THz) radiation detection by junctionless metal-oxide-semiconductor field-effect transistors (JL MOSFETs) was studied and compared with THz detection using conventional MOSFETs. It has been shown that in contrast to the behavior of standard transistors, the junctionless devices have a significant responsivity also in the open channel (low resistance) state. The responsivity for a photolithographically defined JL FET was 70 V/W and the noise equivalent power 460 pW/√Hz. Working in the open channel state may be advantageous for THz wireless and imaging applications because of its low thermal noise and possible high operating speed or large bandwidth. It has been proven that the junctionless MOSFETs can also operate in a zero gate bias mode, which enables simplification of the THz array circuitry. Existing models of THz detection by MOSFETs were considered and it has been demonstrated that the process of detection by these junctionless devices cannot be explained within the framework of the commonly accepted models and therefore requires a new theoretical approach.

Investigation of the S-PIN Diodes for Silicon Monolithic Antennas With Reconfigurable Aperture

Investigations of surface p-i-n (S-PIN) diodes developed for silicon monolithic antennas with reconfigurable aperture have been described. The main criteria for choosing a suitable substrate for the S-PIN diodes have been extensively discussed. Based on this analysis, it has been found that dedicated silicon-on-insulator (SOI) substrates meet the requirements of efficient and lossless wave propagation. Experimental results shown in this paper confirm the applicability of SOI substrates for manufacturing of electrically reconfigurable slot apertures. The results show that S-PIN diodes realized on SOI substrates are suitable for various microwave and millimeter-wave applications.

Monolithic active pixel sensor realized in SOI technology—concept and verification

The paper presents the concept and the verification of a novel silicon monolithic active pixel detector realized in the SOI technology. The reliability and the basic electrical characteristics of the sensor are studied and the sensor sensitivity to the ionising radiation is investigated in details.

High-resolution hybrid pixel sensors for the e+e− TESLA linear collider vertex tracker

Abstract In order to fully exploit the physics potential of a future high-energy e+e− linear collider, a Vertex Tracker, providing high-resolution track reconstruction, is required. Hybrid silicon pixel sensors are an attractive option, for the sensor technology, due to their read-out speed and radiation hardness, favoured in the high-rate environment of the TESLA e+e− linear collider design, but have been so far limited by the achievable single point space resolution. In this paper, a conceptual design of the TESLA Vertex Tracker, based on a novel layout of hybrid pixel sensors with interleaved cells to improve their spatial resolution, is presented.

Development of monolithic active pixel sensor in SOI Technology fabricated on the wafer with thick device layer

Monolithic active pixel detectors fabricated in SOI (Silicon On Insulator) technology are novel sensors of ionizing radiation, which exploit SOI substrates for the integration of readout electronics and a pixel detector. The fully depleted sensing diode has been manufactured under buried oxide (BOX) while read-out circuitry occupies upper silicon layer (‘device layer’). The development of the SOI detectors of ionizing radiation was started as a part of the SUCIMA project. During the project, it was proved that a monolithic SOI detector is a viable option for high-energy physics and medicine. The early prototypes suffered from significant leakage currents and soft breakdowns. These effects limited yield of production. Moreover, the p-wells (formed within the device layer and extended to the interface with the BOX), caused some local potential wells below the BOX at the top of depleted sensor area reducing the effective charge collection efficiency. The use a thicker device layer and optimized technology appeared to be a remedy.