Solution-processed high-k dielectrics for improving the performance of flexible intrinsic Ge nanowire transistors: dielectrics screening, interface engineering and electrical properties

Abstract

Although Ge-based CMOS have attracted sustained research interest for scaling beyond the Si CMOS limitation, Ge-based flexible electronics are still rarely discussed. For Ge-based flexible electronics, seeking proper dielectrics-both with excellent dielectric/Ge interface quality and special temperature compatibility with the polymer supports in the manufacturing process-is still the main challenge. In addition, focusing on solution-processed high-k dielectrics instead of vacuum fabrication technology is a particular concern. Here, we report on our systematic efforts to improve the device performance of flexible intrinsic Ge nanowire transistors on a polyimide substrate with solution-processed high-k dielectric films. Firstly, YO x thin film was determined to be the most suitable candidate among various solution-processed high-k dielectrics (ZrO x , HfO x , TiO x , AlO x , YO x and LaO x ) due to its most promising electrical properties, surface roughness and process temperature. Secondly, the excellent YO x /Ge interface quality was successfully achieved under optimized conditions with a precursor solution concentration of 0.2 M, an annealing temperature of 500 °C and an O 2 annealing atmosphere. Ultimately, benefitting from proper dielectric screening and interface engineering, single intrinsic flexible Ge nanowire transistors were demonstrated, exhibiting excellent operating characteristics comparable to devices on rigid substrates. The devices further show good stability, implying their great potential in flexible electronics.

On the operating mechanisms of flexible microwave inductors and capacitors under mechanical bending conditions

“…For flexible electronics, inorganic single-crystal materials can be processed into nanomembranes only hundreds of nanometers thick by utilizing the methods of reactive ion etching (RIE), wet etching, and transfer techniques. These inorganic single-crystal nanomembranes with high carrier mobilities are thus perfect candidates for flexible wireless communication circuits, and could be compatible with current complementary metal-oxide semiconductor (CMOS) processes [11][12][13][14][15][16]. Recently, a variety of flexible active components (e.g.…”