Vertikálny GaN MOSFET pre výkonové spínacie aplikácie
Vertical GaN MOSFET for power switching applications
Program: SRDA
Project leader: Ing. Kuzmík Ján DrSc.
Annotation: Owing the ever growing demand for the energy volume, energy attainability represents one of the most important issues of today’s society. However, there are great reserves in the energy savings available. According to available analyses, more than 10% of all electricity is ultimately lost in the form of conversion losses. Clearly, even partial improvement in the conversion efficiency can have strong economic impact. As the most of energy is now used for the electronics, corresponding scale of the losses forms at the end-user side, where the electricity is converted into a form suitable for a particular appliance. The main effort towards the conversion efficiency improvements therefore targets the area of power AC/DC and DC/DC converters for consumer and industrial electronics. Significant improvement in the conversion efficiency can be achieved by using GaN based transistors, as they are capable to operate at much higher frequencies with almost three times lower switching losses compared to Si devices.The main goal of the project is the research and development of vertical GaN MOSFET without using p-doping, and gaining the original knowledge on electrical and physical properties of the developed devices. From the quantitative point of view, our proof-of-concept device will target RON<2 mOhm/cm2 and VBD>600 V. An original feature of the proposed concept is utilization of the semi-insulating (SI) GaN as a channel layer (instead of p-type GaN), which blocks the current flow through the transistor at zero gate voltage. To open the transistor channel, positive voltage applied to the gate will be needed to induce down bend-bending in the SI GaN, allowing electron injection from the source to the drift region (along the side walls of SI GaN). This concept therefore represents a unipolar enhancement-mode transistor, while drift region is formed of un-doped GaN with extremely low density of dislocation grown directly on GaN substrate.
Duration: 1.7.2019 – 30.6.2022
Fyzikálne problémy štruktúr MISFET a MISHFET na báze III-V a III-N polovodičov
Physical problems of MISFET and MISHFET structures based on III-V and III-N semiconductors
Program: VEGA
Project leader: Ing. Osvald Jozef DrSc.
Annotation: The project is oriented towards physical problems of III-V and III-N semiconductors. Many problems with these semiconductors are not solved yet or we have not their technological solution. Among these questions we may name in first the problems connected with the physics and chemistry of an interface between a semiconductor and a dielectric, solving of which is crucial for quality of this interface. The density of interface states of the prepared samples and structures depends directly on the solution of these problems and a possible presence of Fermi level pinning at the semiconductor surface, too. By III-V MISFET structures we want to study frequency dependence of capacitance curves. There are theories that in accumulation a dispersion of the capacitance is caused by a low density of states at the bottom of the conduction band and that the capacitance increase in inversion is connected with the states in the middle of the gap. We shall try to verify these theories or maybe modify them on the basis of the obtained results.
Duration: 1.1.2017 – 31.12.2020
MEMS senzory na báze nanoštruktúr tenkých vrstiev pre detekciu plynov a stopových ťažkých kovov
MEMS sensors based on nanostructured thin films for gas detection and determination of heavy metals
Program: VEGA
Project leader: RNDr. Haščík Štefan PhD.
Duration: 1.1.2012 – 31.12.2015