In the presented work solvent-free film preparation from tailored molecular glass resists, their thermal analysis, the characterization of etch resistance for plasma etching transfer processes, and the evaluation of the patterning performance using scanning probe lithography (SPL) tools, in particular electric field and thermal based SPL, are demonstrated. Therefore a series of fully aromatic spiro-based and tris-substituted twisted resist materials were systematically investigated. The materials feature very high glass transition temperatures of up to 173 °C, which allows solvent-free thin film preparation by physical vapor deposition (PVD) due to their high thermal stability. The PVD prepared films offer distinct advantages compared to spin coated films such as no pinholes, defects, or residual solvent domains, which can locally affect the film properties. In addition, PVD prepared films do not need a post apply bake (PAB) and can be precisely prepared in the nanometer range layer thickness. An observed sufficient plasma etching resistance is promising for an efficient pattern transfer even by utilizing only 10 nm thin resist films. Their lithographic resolution potential is demonstrated by a positive and a negative tone patterning using electric field, current controlled scanning probe lithography (EF-CC-SPL) at the Technical University of Ilmenau or thermal scanning probe lithography (tSPL) investigations at the IBM Research - Zurich. High resolution tSPL prepared patterns of 11 nm half pitch and at 4 nm patterning depth are demonstrated.
The performance of novel molecular glass resists is demonstrated in this work for the purposes of performing nano-pattern transfer. In order to improve the etch durability, post apply bake (PAB) and mixing two resists platforms were investigated. These resists showed a promising etch durability for efficient pattern transfer with films as thin as 5 nm. Etch rate, surface roughness, evolution of the refractive index of these materials are presented to establish a good baseline and select appropriate candidate materials for patterning beyond-CMOS.
The presented work deals with molecular glass resist materials based on (i) calixresorcinarene resist systems, (ii) twisted fully aromatic biscarbazole-biphenyl materials, and (iii) fully aromatic spiro resist materials as new promising materials for Scanning Probe Lithography (SPL). Because of the non-chemically amplified resist nature and the absence of corresponding material diffusion, the novel SPL resists have the potential to increase the patterning resolution capabilities at a simultaneous reduction of the edge roughness (LER). In addition, these low molecular weight molecular glasses offer the advantage of solvent-free film preparation by physical vapor deposition (PVD). The PVD prepared films offer a number of advantages compared to spin coated ones such as no more pinholes, defects, or residual solvent domains, which can locally affect the film properties. These high-quality PVD films are ideal candidates for the direct patterning by SPL tools. Presented highlights are the thermal scanning probe lithography (tSPL) investigations at IBM Research - Zurich and the patterning by using electric field, current controlled scanning probe lithography (EF-CC-SPL) at the Technical University of Ilmenau. Further investigations on film forming behavior, etch resistance, and etch transfer are presented. Owing to the high-resolution probe based patterning capability in combination with their improved etch selectivity compared to reference polymeric resists the presented molecular glass resists are highly promising candidates for lithography at the single nanometer digit level.
Within this work we present the synthesis and applications of a novel material designed for n-type self-assembled monolayer field-effect transistors (SAMFETs). Our novel perylene bisimide based molecule was obtained in six steps and is functionalized with a phosphonic acid linker which enables a covalent fixation on aluminum oxide dielectrics. The organic field-effect transistors (OFETs) were fabricated by submerging predefined transistor substrates in a dilute solution of the molecule under ambient conditions. Investigations showed a thickness of about 3 nm for the organic layer which is coincides to the molecular length. The transistors showed bulk-like electron mobilities up to 10<sup>-3</sup> cm<sup>2</sup>/Vs. Due to the absence of bulk current high on/off-ratios were achieved. An increase of the electron mobility with the channel length and XPS investigations point to a complete coverage of the dielectric with a dense monolayer. In addition, a p-type SAMFET based on a thiophene derivative and our new n-type SAMFET were combined to the first CMOS bias inverter based solely on SAMFETs.