Properties and characterization of ALD grown dielectric oxides for MIS structures

We report on an extensive structural and electrical characterization of under-gate dielectric oxide insulators Al2O3 and HfO2 grown by Atomic Layer Deposition (ALD). We elaborate the ALD growth window for these oxides, finding that the 40-100 nm thick layers of both oxides exhibit fine surface flatness and required amorphous structure. These layers constitute a base for further metallic gate evaporation to complete the Metal-Insulator-Semiconductor structure. Our best devices survive energizing up to ~3 MV/cm at 77 K with the leakage current staying below the state-of-the-art level of 1 nA. At these conditions the displaced charge corresponds to a change of the sheet carrier density of 3 \times 1013 cm-2, what promises an effective modulation of the micromagnetic properties in diluted ferromagnetic semiconductors.Comment: 8 pages, 5 figures, 14 reference

Properties of thin films of high-k oxides grown by atomic layer deposition at low temperature for electronic applications

Thin films of high-k oxides are presently used in semiconductor industry as gate dielectrics. In this work, we present the comparison of structural, morphological and electrical properties of binary and composite layers of high-k oxides that include hafnium dioxide (HfO2), aluminum oxide (Al2O3) and zirconium dioxide (ZrO2). We deposit thin films of high-k oxides using atomic layer deposition (ALD) and low growth temperature (60–240 °C). Optimal technological growth parameters were selected for the maximum smoothness, amorphous microstructure, low leakage current, high dielectric strength of dielectric thin films, required for gate applications. High quality of the layers is confirmed by their introduction to test electronic structures, such as thin film capacitors, transparent thin film capacitors and transparent thin film transistors. In the latter structure we use semiconductor layers of zinc oxide (ZnO) and insulating layers of high-k oxide grown by the ALD technique at low temperature (no more than 100 °C)

Characterization of n-ZnO/p-GaN Heterojunction for Optoelectronic Applications

An important feature of zinc oxide and gallium nitride materials are their similar physical properties. This allows to use them as a p-n junction materials for applications in optoelectronics. In earlier work we presented use of ZnO as a transparent contact to GaN, which may improve external efficiency of LED devices. In this work we discuss properties of a n-ZnO/p-GaN heterostructure and discuss its optimization. The heterostructure is investigated by us for possible applications, e.g. in a new generation of UV LEDs or UV light detectors

ACTA PHYSICA POLONICA A Schottky Junctions Based on the ALD-ZnO Thin Films for Electronic Applications

The ZnO-based Schottky diodes revealing a high rectication ratio may be used in many electronic devices. This paper demonstrates several approaches to obtain a ZnO-based Schottky junction with a high rectication ratio. The authors tested several methods such as: post-growth annealing of the ZnO layer, acceptor (nitrogen) doping, as well as the ZnO surface coating with a properly chosen dielectric material. The inuence of these approaches on the diode's rectication ratio together with modeling based on the dierential approach and thermionic emission theory are presented

Schottky Junctions Based on the ALD-ZnO Thin Films for Electronic Applications

The ZnO-based Schottky diodes revealing a high rectification ratio may be used in many electronic devices. This paper demonstrates several approaches to obtain a ZnO-based Schottky junction with a high rectification ratio. The authors tested several methods such as: post-growth annealing of the ZnO layer, acceptor (nitrogen) doping, as well as the ZnO surface coating with a properly chosen dielectric material. The influence of these approaches on the diode's rectification ratio together with modeling based on the differential approach and thermionic emission theory are presented