Anna Benčurová

The AZ 5214E Resist in EBDW Lithography and its Use as a RIE Etch–Mask in Etching Thin Ag Layers in N2 Plasma

Abstract In this article we describe the electron-beam direct-write (EBDW) lithography process for the AZ 5214E photoresist which is, besides its sensitivity to UV radiation, sensitive also to electrons. An adapted process flow is provided. At the same time we examine the resistance of this resist to RIE and its suitability as an etch-mask for etching thin Ag layers in N2 plasma. A comparison with several chosen resists (PMMA, ma-2405, ma-N 1402, SU-8 2000) is provided.

Patterning of structures by e-beam lithography and ion etching for gas sensor applications

This work deals with a method of preparation of nanometer structures for a gas detector based on e-beam lithography and ion etching of a thin TiO2 film. The aim was the fabrication of a gas sensor with meander or comb structures of nanometer dimensions. This is of importance since both the size of the contacts and the layer thickness affect the sensors sensitivity.

Limitations of variable shaped electron beam lithography for advanced research and semiconductor applications

This paper reports on the study of limitations of variable shaped electron beam lithography (EBL) as flexible high-resolution pattern generators for the fabrication of high quality photomasks required for many applications in sensors and microsystems development, including packaging applications. For this purpose, the case of 50×50 nm2 electron beam shape at 40 keV electron energy and a high-resolution e-beam resist Hydrogen Silsesquioxane (HSQ) were utilized. Various process parameters, which determine the accuracy of the resist profiles and the size of structures, such as solubility rates, dependences of the linewidth on the exposure dose, lithographic resolution, etching capabilities of HSQ and their influence on the limitations of variable shaped EBL, are studied.

The effect of process parameters and annealing on the properties of Ti/Pt films for miniature temperature sensors

We present a Pt film temperature element of the size of 1.5×1.5 mm2 with the meander width of 20 μm. It was investigated the effect of Pt film thickness prepared on alumina ceramics and the post-deposition annealing process on structural and electrical properties. As-deposited Pt films are polycrystalline with strongly preferred orientation on the (111) plane and the grains size is about 20 nm. The peak strength of (111) increased after annealing for all investigated samples and also the grain sizes increased up to 67 nm. Annealed Pt films exhibit a lower resistivity in comparison with the as-deposited films.

Study of negative electron beam nanoresist HSQ on GaAs substrate

The aim of this paper is to characterize Hydrogen Silsesquioxane (HSQ) inorganic negative electron resist on GaAs substrate at 40 keV electron energy. The influence of process parameters on resist profiles was investigated with the aim of obtaining vertical sidewalls. The values of the proximity effect function parameters (β_f, β_b and η_E) were calculated using Monte Carlo approach. Observation of HSQ resist profiles were done for a set of linewidth dimensions.

Simple patterning method of sub-micro- and nanometer structures for gas sensor

In this study, a simple patterning method of submicrometer structures is proposed for gas sensor development. Comb-like electrodes patterned in thin Pt layer were proposed to measure gas sensor electrical conductivity. Negative resist SU-8 was used as a masking layer for ion etching of electrodes in 35 nm Pt layer on sapphire substrate. This method was applied for the patterning of the comb-like structures with submicrometre dimensions for gas sensor conductivity measurements.

Optical properties of LEDs with patterned 1D photonic crystal

In this paper we focus on the application of the one-dimensional photonic crystal (1D PhC) structures on the top of Al0.295Ga0.705As/GaAs multi-quantum well light emitting diode (MQW LED). 1D PhC structures with periods of 600 nm, 700 nm, 800 nm, and 900 nm were fabricated by the E-Beam Direct Write (EBDW) Lithography. Effect of 1D PhC period on the light extraction enhancement was studied. 1D PhC LED radiation profiles were obtained from Near Surface Light Emission Images (NSLEI). Measurements showed the strongest light extraction enhancement using 800 nm period of PhC. Investigation of PhC LED radiation profiles showed strong light decoupling when light reaches PhC structure. Achieved LEE was from 22.6% for 600 nm PhC LED to 47.0% for 800 nm PhC LED. LED with PhC structure at its surface was simulated by FDTD simulation method under excitation of appropriate launch field.

Far Field Measurements of Phc Led Prepared by E–Beam Lithography

Abstract The paper deals with optical characterization of the Al0.295Ga0.705As/GaAs multi-quantum well light emitting diode (LED) structure with photonic crystal (2D PhC) patterned on the top of the structure using Electron Beam Direct Write Lithography (EBDWL). Light-current characteristics measured by integrating sphere shows increase of extracted light intensity as 21.1%. Additionally, extracted light intensity was studied by far-field measurements as a complementary method to light-current characteristics. The far-field measurements show increase of extracted light intensity as 31.2%. We suggest this method as more suitable for evaluation of extracted light intensity because it omits emission from edges of the LED and thus light is measured only from the area where PhC is patterned

Estimation of exposure parameters of chosen e-beam resists using variable shaped e-beam pattern generator

In this article we present results from lithography experiments on PMMA (positive tone), and HSQ Fox-12 and SU-8 (negative tone) resists carried out on the ZBA variable shaped e-beam pattern generators. In order to obtain the necessary information needed for the optimization of the exposure control Point Spread Function PSF, several lithography tests are mentioned. The carried out measurements and analysis of the results help us in obtaining important information about the resists and exposure processes and enable us to practically verify the suggested methods of parameters extraction for a reliable exposure model.