The comparison of the growth models of silicon nitride ultrathin films fabricated using atmospheric pressure plasma and radio frequency plasma

Abstract

The reaction process model during initial nitridation of Si (111) using atmospheric pressure plasma source was constructed and it was compared to that using a radio frequency plasma source. In atmospheric pressure plasma, emission lines from the N2 second positive system were dominantly observed. By exposing the atmospheric pressure plasma to Si substrate at the temperature ranging from 25to500°C, silicon nitride films with a thickness below 1.8nm were formed. In order to study the nitridation process, the changes in the film thickness against the substrate temperature and nitridation time were systematically studied at a pressure ranging from 50to700Torr. The film thickness increases with increasing the nitridation pressure below 400Torr and it saturates above 500Torr. It was completely regardless of the substrate temperature. From the time dependence of the film thickness at various nitridation pressures, it was revealed that these experimental results were well fitted to a Langmuir-type adsorption model. In the case of nitridation using atmospheric pressure (AP) plasma, molecular species play an important role for nitridation without thermal diffusion. The difference of silicon nitride films fabricated using AP plasma and rf plasma originates from the difference in the active species.

Orientation Control of ZnO Films Deposited Using Nonequilibrium Atmospheric Pressure N2/O2Plasma

“…We have reported that the N 2 second positive system (N 2 2ps) was predominantly observed in atmosphericpressure N 2 plasma and it retained a reactivity high enough to accomplish room-temperature nitridation of a silicon wafer. [21][22][23] There is quite a high potential energy state of above 10 eV from the ground state in the reaction process of N 2 2ps, 30) which can be expected to supply precursors a high energy to form highly 0001-oriented ZnO films. Therefore, we investigated the change in the optical emission spectra by varying the O 2 =ðO 2 þ N 2 Þ ratio systematically from an oxygen-rich gas composition to a nitrogen-rich gas composition.…”

“…Our research group has reported the room-temperature nitridation of Si [21][22][23] and Ge, 24) and dense SiO 2 can also be formed using AP N 2 plasma with a small amount of O 2 even in the downstream (remote) region. 25,26) Moreover, we have succeeded in the formation of ZnO films at a substrate temperature as low as 200 C using AP N 2 /O 2 plasma.…”

Self-focusing of a whistler propagating at an angle to the magnetic field in a plasma

“…Whistlers have proved to be important diagnostic tools for these regions. They also play an important role in many applications, ranging from space plasma research [3][4][5] to basic plasma physics experiments [6][7][8], radio frequency (rf) plasma sources [9][10][11][12], rf plasma in nanotechnology [13][14][15][16], plasma processing [17][18][19][20] and plasma thrusters [21]. Large-amplitude whistlers propagate in well-defined ducts, created by ponderomotive nonlinearity setting off diffraction divergence.…”

Method for real-time measurement of nitrogen atom density in atmospheric pressure post-discharge flows

“…Owing to this feature, remote plasma processing has significant advantages; for instance, it alleviates the configurative limitations of objects, reduces damage caused by high-energy ion bombardments and facilitates the inline process [4]. Although oxygen-containing gasses or air discharge have often been used, pure nitrogen or a mixture of nitrogen and rare gases have the potential to be used, such as in surface nitridation or treatment of materials in which oxidation should be avoided [5][6][7][8].…”