Printing of electronics has been gaining a lot of attention over the past decade as a low cost alternative to conventional electronic fabrication methods. A significant development in this area was the possibility to print a silicon precursor, polydihydrosilane, which can directly be transformed into polycrystalline silicon by an excimer laser treatment. Due to the limited laser heat diffusion, low-cost flexible substrates such as plastics and even paper could be used that typically have low thermal budgets. Since the silicon precursor is sensitive to ultraviolet light and may transform in a photochemical reaction, the question arises whether the excimer laser crystallization is predominantly photochemical or rather a thermal reaction. In this work, a model is developed and reflected to experimental data, to understand the physics behind the process. Through finite-element analysis and experimental characterizations it was observed that the physics behind the process was predominantly thermal, and that instead of an intermediate transition to a-Si, a direct transformation to poly-Si exists. By understanding this process, the treatment can be optimized or more efficient tools can be used that would enable a low cost production of high performing silicon devices@en

Printing of electronics is pursued as a low-cost alternative to conventional manufacturing processes. In addition, owing to relatively low process temperatures, flexible substrates can be used enabling novel applications. Among flexible substrates, paper was found to be a particularly interesting candidate, since it has an order of magnitude lower price than low-cost polymer alternatives, and is biodegradable. As ink materials, organic and metal-oxide semiconductors are thoroughly being investigated; however, they lack in electric performance compared to silicon in terms of device mobility, reliability, and energy efficiency. In recent years, liquid precursors for silicon were found and used to create polycrystalline silicon (poly-Si). However, fabrication of transistors on top of low-cost flexible substrates such as paper has remained an outstanding challenge. Here we demonstrate both p-channel and n-channel poly-Si thin-film transistors (TFTs) fabricated directly on top of paper with field-effect mobilities of 6.2 and 2.0 cm2/V s, respectively. Many fabrication challenges have been overcome by limiting the maximum process temperature to approximately 100 °C, and avoiding liquid chemicals commonly used for etching and cleaning. Patterning of poly-Si has been achieved by additive selective crystallization of the precursor film using an excimer laser. This work serves as a proof of concept, and has the potential to further improve device performance. Owing to the low-cost, biodegradable nature of paper, and the high performance, reliability, and energy efficiency of poly-Si TFTs, this work opens a pathway toward truly low-cost, low-power, recyclable applications including smart packages, biodegradable health monitoring units, flexible displays, and disposable sensor nodes.@en

High-performance Si thin-film transistors (TFTs) are fabricated inside a single, location-controlled grain with gate SiO/sub 2/ deposited by electron cyclotron resonance plasma enhanced chemical vapor deposition (ECR-PECVD). The position of the large grains is controlled by /spl mu/-Czochralski (grain-filter) process with excimer-laser crystallization. Owing to the low interface trap density of ECR-PECVD SiO/sub 2/ the single-grain Si TFTs showed a smaller subthreshold swing of 0.45 V/decade, in addition to a higher field-effect mobility for electrons of 460 cm/sup 2//Vs than that with low-pressure chemical-vapor deposited (LPCVD) SiO/sub 2/.@en

High-performance Si thin-film transistors (TFTs) are fabricated inside a single, location-controlled grain with gate SiO/sub 2/ deposited by electron cyclotron resonance plasma enhanced chemical vapor deposition (ECR-PECVD). The position of the large grains is controlled by /spl mu/-Czochralski (grain-filter) process with excimer-laser crystallization. Owing to the low interface trap density of ECR-PECVD SiO/sub 2/ the single-grain Si TFTs showed a smaller subthreshold swing of 0.45 V/decade, in addition to a higher field-effect mobility for electrons of 460 cm/sup 2//Vs than that with low-pressure chemical-vapor deposited (LPCVD) SiO/sub 2/.@en

High-performance Si thin-film transistors (TFTs) are fabricated inside a single, location-controlled grain with gate SiO/sub 2/ deposited by electron cyclotron resonance plasma enhanced chemical vapor deposition (ECR-PECVD). The position of the large grains is controlled by /spl mu/-Czochralski (grain-filter) process with excimer-laser crystallization. Owing to the low interface trap density of ECR-PECVD SiO/sub 2/ the single-grain Si TFTs showed a smaller subthreshold swing of 0.45 V/decade, in addition to a higher field-effect mobility for electrons of 460 cm/sup 2//Vs than that with low-pressure chemical-vapor deposited (LPCVD) SiO/sub 2/.@en

Solution-processing has gained widespread attention over the past years due to their potential low-cost advantage in terms of fabrication of electronics as well as application to flexible electronics. Cyclopentasilane is used for the solution-based processing of silicon. As a liquid, the material has the potential to be applied directly on low-cost flexible substrates that generally have a low thermal budget, by annealing the liquid using an excimer laser treatment. So far, electronics based on this material have only been demonstrated on rigid and high cost substrates. In this work, silicon has been applied as a solution on top of a paper substrate and processed into PMOS and NMOS thin-film transistors (TFTs). The maximum fabrication temperature was limited to approximately 100° C. By being able to fabricate devices on top of a paper substrate, a pathway opens towards new applications that combine the true low-cost and biodegradability with the high performance of silicon electronics.@en

Silicon can be printed using liquid silicon ink, which is a mixture of polymerized cyclopentasilane (CPS) and a solvent. Thermal annealing higher than 350oC of this material, however, was necessary, to convert it to solid silicon, which prevented its usage on inexpensive substrates with a limited thermal budget. We review a novel method that forms polycrystalline silicon (poly-Si) patterns directly on paper using the same liquid silicon with doctor-blade coating and local irradiation of excimer-laser with room temperature process. We review also the process and electrical properties of poly-Si TFTs fabricated on the paper. This technique will breakthrough the printed electronics by enabling applications such as fast printed electronics that are inexpensive, fully-recyclable, biodegradable and even edible.@en