Standard CMOS Fabrication of a Sensitive Fully Depleted Electrolyte-Insulator-Semiconductor Field Effect Transistor for Biosensor Applications

Microfabricated semiconductor devices are becoming increasingly relevant for detection of biological and chemical components. The integration of active biological materials together with sensitive transducers offers the possibility of generating highly sensitive, specific, selective and reliable biosensors. This paper presents the fabrication of a sensitive, fully depleted (FD), electrolyte-insulator-semiconductor field-effect transistor (EISFET) made with a silicon-on-insulator (SOI) wafer of a thin 10-30 nm active SOI layer. Initial results are presented for device operation in solutions and for bio-sensing. Here we report the first step towards a high volume manufacturing of a CMOS-based biosensor that will enable various types of applications including medical and environmental sensing

Capteur d’hydrogène mos et méthode d’intégration à une technologie de transistor FDSOI

Abstract: hydrogen can be used as an energy carrier (storage) by the renewable energy industry as well as the automotive industry (fuel cell). Other industries already use hydrogen such, food processing and petroleum refineries. Hydrogen is odorless, transparent, and has a lower explosive limit of 4 %. Reliable, fast sensor are essential tools for a hydrogen safe environment. The work of this thesis provides a semiconductor-based hydrogen sensing solution. A MOS capacitor using a CMOS compatible novel Pt/Ti/ALD-Al2O3/p-Si stack. The Pt/Ti/Al2O3 sensing interface materials thicknesses are 100/5/38 nm respectively. The device can detect very low concentrations < 20 ppm. Furthermore, for a concentration of 500 ppm the response time is 56 s. the impact of testing conditions such temperature, and total gas flow have been studied. Results show that at 60℃ the device does not respond to hydrogen. And at 80℃ or higher the sensing response time is significantly reduced with increasing temperature. Furthermore, the total gas flow has an impact on the device response time and shows that a portion of the time response delay can be attributed to the chamber’s volume. Moreover, a heterogeneous integration method has been designed and presented. The latter represents a great tool for a flexible prototyping of sensors using FDSOI transistor technology. The integration has been simulated and results show promising results. The capacitive coupling feature in the FDSOI between the front and back gate is used to amplify the potential variation at the front gate. For instance, a 0.3 V hydrogen induced dipole potential can be amplified by a factor of 14 x.Le travail de cette thèse comprend la conception et la fabrication d’une technologie de capteur d’hydrogène basée sur une structure MOS. La structure est composée d’un empilement de Pt/Ti/Al2O3/p-Si. Les épaisseurs des matériaux utilisés pour la fabrication sont 100/5/38 nm (Pt/Ti/Al2O3) sur un substrat de silicium. Le capteur est capable de détecter de très faibles concentrations < 20 ppm. De plus, pour une concentration de 500 ppm, le temps de réponse est 56 s. L’impact de plusieurs conditions de test, comprenant la température et le débit total dans la chambre a été évalué. Les résultats montrent qu’à 60℃ le dispositive n’est pas capable de détecter la présence d’hydrogène. Cependant, à partir d’une température de 80℃, la réponse est très importante et le temps diminue pour encore des températures plus élevées. Le débit total dans la chambre a aussi démontré un impact sur le temps de réponse du capteur. Ce qui est aussi relié au volume de la chambre. Une intégration hétérogène ensuite a été conçue et présentée. Cette dernière est un outil flexible pour le prototypage avec des technologies de transistor FDSOI. L’intégration des deux dispositifs a été effectuée et montre de résultats prometteurs. Le couplage capacitif entre la grille avant et la grille arrière du transistor FDSOI permet d’amplifier le signal du capteur. Par exemple, une variation de potentiel de 0.3 V peut être amplifier par un facteur de 14 x, donc 4.19 V

Cellulose Nanocrystal Chiral Structures for Electronics and Photonics

This dissertation reports on the integration of cellulose nanocrystals (CNCs) as photonic films into optoelectronic devices, where the films’ inherent left-handed mesoporous chiral nematic structure acts as a circular polarized light (CPL) filter in the visible light range. The outcome demonstrates for the first time micro- scopic semiconducting devices based on cellulose, capable of producing specific electronic outputs when irradiated with either left- or right- handed CPL (LCPL and RCPL, respectively). For this proof-of-concept two distinct optoelectronic devices are targeted: a thin-film field-effect transistor and a thin-film photodiode, spanning the whole visible electromagnetic spectrum. The devices are jointly developed each one with a specific type of CNC, presenting photonic bandgaps that are tuned for the active layer of the devices. On the one hand, lab-produced (home-made CNCs – HM-CNCs) are synthesized through sulfuric acid hydrol- ysis, yielding HM-CNC films with a photonic bandgap in the blue/UV region. On the other hand, industrially produced Na neutralized spray-dried CNCs by CelluForce (C-CNCs) are studied on behalf of their redispersion in water to yield C-CNC films with a photonic bandgap in the green/red region. The work is essentially divided into three main parts: • Study of liquid crystalline and photonic properties of HM-CNCs and C- CNCs in aqueous suspensions (Chapter 3) • Implementation of HM-CNCs into field-effect transistors (Chapter 5) • Implementation of C-CNCs into thin-film photodiodes (Chapter 6) The main objective of Chapter 5 deals with the implementation of HM-CNCs films, optimized through the first Objective in Chapter 3, into field-effect tran- sistors based on amorphous indium-gallium-zinc-oxide (a-IGZO) as the semicon- ductor. In the resulting devices the HM-CNC films take simultaneously the role of the devices’ dielectric as a solid-state electrolyte and as a photonic filter for CPL. Consequently, this study encompasses two sub-objectives, connected firstly to the study of the electrochemical properties of these films and their success- ful integration into field-effect transistors without compromising self-assembly behavior. And secondly, successful proof of CPL sensing capabilities of these devices. The final study shows the incorporation of C-CNC films, into amorphous silicon-based thin-film photodiodes, achieving a light sensor capable of discrimi- nating between RCPL and LCPL. The spectral response of the fabricated photo- diodes is maximum for specific wavelengths in the green/red region. Irradiating the devices in these wavelengths they produce photocurrents that are over 50% distinct between RCPL and LCPL. Fast transient responses (on the order of ms) of CPL are shown with possible logic operations, as well as humidity sensing. Films produced through the methods described in Chapter 3 show promis- ing properties for their application in sensing, co-templating, enantioselectivity, photonic pigments or anti-counterfeiting. The insights presented in Section 5.1 contribute to applications in solid-state ionics of mesoporous structures or the combination of optically active electrolytes capable of providing unique func- tionalities in ion-gated transistors and circuitry. Finally, the types of devices pro- duced in Section 5.2 and Chapter 6 may find applications in photonics, emission, conversion, or sensing with CPL but also imaging, spintronics, optoelectronic counterfeiting or information processing with logic states that depend solely on the handedness of the incident light.Esta dissertação é dedicada ao estudo de nanocristais de celulose (cellulose nanocrystals - CNCs) e à sua integração como filmes fotónicos em dispositivos optoelectrónicos, explorando a sua estrutura nemática quiral com orientação de rotação para esquerda como um filtro de luz polarizada circularmente (circu- lar polarized light - CPL) no comprimento de onda visível. Os resultados deste trabalho demonstram dispositivos microscópicos à base de celulose, capazes de responder com sinais elétricos específicos quando irradiados por CPL à esquerda (LCPL) ou CPL à direita (RCPL). Para esta prova-de-conceito são destacados dois dispositivos optoelectrónicos distintos: transístores e fotodíodos. Os dispositivos desenvolvidos incorporam diferentes tipos de CNCs com um hiato fotónico espe- cífico correspondente à região de absorção das camadas ativas dos dispositivos. De um lado são sintetizados CNCs em laboratório (home-made CNCs – HM-CNCs) que resultarão filmes fotónicos com um hiato no Azul/UV. De outro lado, CNCs comerciais da CelluForce (C-CNCs), em forma de pó. A redispersão desse tipo de CNCs em água é investigada, e resulta em filmes fotónicos com um hiato na região do verde/vermelho. Essencialmente, o trabalho está divido em três partes principais: • Estudo das propriedades líquidas cristalinas e fotónicas de suspensões aquo- sas de HM-CNCs e C-CNCs (Capítulo 3) • Implementação de HM-CNCs em transístores (Capítulo 5) • Implementação de C-CNCs em fotodíodos (Capítulo 6) Capítulo 5 estuda a implementação de filmes de HM-CNCs, otimizados no objetivo do Capítulo 3, em transístores de efeito de campo onde o semicondutor é o óxido de índio-gálio-zinco amorfo (a-IGZO). Nos dispositivos finais, o filme de HM-CNCs assume uma dupla funcionalidade: funciona como o dielétrico do transístor (na forma de um eletrólito de estado sólido), e atua como um filtro seletivo de CPL. Logo, esta parte está divida em dois sub-objetivos: a primeira estuda as propriedades eletroquímicas dos filmes de HM-CNCs, e a sua integração em transístores de efeito de campo sem perda das propriedades de self-assembly, enquanto a segunda parte é dedicada à prova de conceito da deteção seletiva de CPL. O estudo final demonstra a incorporação de filmes de C-CNCs em fotodíodos baseados em silício amorfo, que resulta em sensores de luz capazes de diferenciar entre os dois estados de CPL. A resposta espetral dos fotodíodos é máxima para comprimentos de onda específicos na região do verde e do vermelho. Ao irradiar os dispositivos finais nesses comprimentos de onda com CPL, estes apresentam uma diferença de 50% nas foto-correntes medidas para cada um dos dois estados de CPL. Os dispositivos finais mostram tempos de resposta rápidos (na ordem dos ms), o que os habilita a serem implementados em circuitos para operações lógicas baseadas em estados de polarização e também como sensores de humidade. Filmes produzidos no Capítulo 3, mostram propriedades promissoras para a sua aplicação em sensores, pigmentos fotónicos, e na área de anti-falsificação e segurança. Os resultados da Secção 5.1 contribuem para aplicações em iónica de estado sólido de estruturas mesoporosas, ou a combinação de eletrólitos ótica- mente ativos. Por fim, os dispositivos fabricados na Secção 5.2 e Capítulo 6, podem ser aplicados em áreas de fotónica, emissão, conversão ou sensores de CPL, mas também imagiologia, spintrónica, anti-falsificação por dispositivos optoelectró- nicos, ou processamento de informação com estados lógicos que dependem da polarização da radiação incidente

A transistor based sensing platform and a microfluidic chip for a scaled-up simulation of controlled drug release

The framework of my thesis are Biomedical (or Biological) Microelectromechanical Systems (BioMEMSs). Two fields in which this discipline is involved are sensors and fluidics. Functionalized organic materials are under investigation to be the means for target biological sensing, and sensors are evolving to be integrated in fluidics platforms in order to produce in the future new small portable diagnostic devices. On the other hand one of the challenges of micro and nanofluidic technology is the fabrication of drug release devices, in order to control the amount of drug present in an organism. In this thesis these two arguments are considered. First we will discuss the implementation of a process oriented to the fabrication of an hybrid Organic Field Effect Transistor (OFET) with sensing capabilities from the semiconductive layer. In the second part we will show the fabrication process of a silicon based structure for the scaled-up characterization of drugs in nanochannels for controlled drug release. The characterization will consider charged microspheres playing the role of drugs to be tracked with a microscope. We will highlight also the possibility of implementing the transistor related technology in nanofluidic systems for the electronic controlled drug release

Index to 1981 NASA Tech Briefs, volume 6, numbers 1-4

Short announcements of new technology derived from the R&D activities of NASA are presented. These briefs emphasize information considered likely to be transferrable across industrial, regional, or disciplinary lines and are issued to encourage commercial application. This index for 1981 Tech Briefs contains abstracts and four indexes: subject, personal author, originating center, and Tech Brief Number. The following areas are covered: electronic components and circuits, electronic systems, physical sciences, materials, life sciences, mechanics, machinery, fabrication technology, and mathematics and information sciences