Marc Chason

Printed Organic Semiconducting Devices

Recent improvements in carrier mobility, environmental stability, and advancements in p- and n-type organic semiconductor materials have resulted in reports of device operation suitable for low-functionality, low-cost products. Deposition of solution-processable materials that enable the use of low-cost, high-speed deposition techniques such as screen printing, spin coating, and conventional graphic arts printing technologies have also recently been demonstrated. The material requirements necessary to realize these products, an organic transistor device structure that can be fabricated with these materials via printing processes, and the resulting device performance are presented and discussed. The use of standards and their impact on driving technology to commercialization are also addressed.

In situ x‐ray reflectivity measurements of thin film structural evolution

X‐ray reflectivity using energy dispersive x‐ray detection has been used to investigate the characteristics of vacuum‐deposited thin films. A resolution of 0.3 nm for thicknesses in the range 3–200 nm and of 0.05 nm for roughness in the range 0.1–3 nm has been demonstrated. Furthermore, it is shown that by using energy dispersive detection, spectra can be obtained in less than 500 s allowing real time studies to be performed. Thin, discrete Cr/Al deposits on quartz substrates have been investigated, and the presence of a 1.5 nm thick Al/Cr intermetallic layer formed during room‐temperature deposition has been determined. During annealing at 250 °C, the Cr layer thickness decreases linearly with time until approximately 4 nm is consumed in additional intermetallic formation; further annealing does not change the Cr layer thickness.

Free-standing quantum dots for electronic applications

Free-Standing Quantum dots (FSQdot), also known as nano-crystals, are semiconductors composed of II-VI, III-V, or IV-VI materials. Ranging in size from 2-10 nanometers in diameter, these FSQdots have size-tunable band gaps. Unlike Qdots produced on semiconductor wafers, FSQdots can be manufactured using scalable colloidal solution chemistry. These FSQdots have high photo-luminescence quantum efficiencies, good thermal and photo-stability, narrow emission line widths (atom-like spectral emission), and are compatible with solution processing. Solution processable FSQdots can be modified using innovative surface functionalization schemes. Once appropriately functionalized, the FSQdots can be incorporated into printable inks and bound to surfaces. These capabilities unlock a realm of possibilities for producing novel commercial electronic products, from unique surface coatings to new display constructions.

Microfluidic systems on a printed wiring board platform

Purpose – The purpose of this paper is to present the development of printed wiring board (PWB)‐based microfluidic building blocks and their integration into systems for DNA amplification and electronic detection.Design/methodology/approach – Technologies from embedded passives (EP) and photolithographic high‐density interconnect are integrated into a traditional PWB platform to enable multifunctional electrochemical sensors for on‐chip detection of biological assays.Findings – PWB materials and processes can be applied to develop microelectromechanical systems (MEMS) and microfluidic systems. On‐chip heaters using EP have been demonstrated with excellent accuracy. The on‐chip heaters can be used for localized temperature control as well as heat air pumps. The integration of EP and microchannels is a promising approach to add functionalities to the PWB‐based microsystems.Research limitations/implications – Further integration of microchannels with the embedded heaters and electrochemical sensors will incr...

RF‐MEMS switches on a printed circuit board platform

Purpose – The purpose of this paper is to present a new class of printed circuit board (PCB)‐based, radio frequency micro‐electro‐mechanical systems (RF‐MEMS) switches and to describe the packaging method and evaluate performance.Design/methodology/approach – Traditional PCB materials and processes were combined with photolithographic high‐density interconnect (HDI) and MEMS to form 3D high‐performance RF switches.Findings – A new type of MEMS RF switch has been developed on a PCB platform. Using processes analogous to those used for silicon MEMS, PCB, and HDI technologies were utilized to fabricate these 3D structures. The PCB‐based microstructures are “mil‐scale” rather than the “micro‐scale” of silicon MEMs. A co‐fabrication packaging method for the MEMS RF switch was also developed. The PCB‐based MEMS switches have demonstrated excellent RF performance and “hot‐switching” RF power‐handling capability. PCB‐based MEMS RF switches have the advantages of low cost and amenability to scale‐up for a high deg...