Improved current–voltage characteristics of downstream plasma enhanced chemical vapor deposition SiNx deposited at low temperature by using He as a dilution gas

Abstract

We have compared the current–voltage characteristics of silicon nitrides prepared from the two gas combinations N2/NH3/SiH4 (N2–SiNx) and He/NH3/SiH4 (He–SiNx) at temperatures between 100 and 350 °C. A downstream plasma enhanced chemical vapor deposition reactor with a non-ECR microwave plasma source has been used. While N2–SiNx with reasonable electrical properties requires deposition temperatures of about 350 °C, the characteristics of He–SiNx even improve at decreasing process temperatures. Almost identical current–voltage characteristics are found for both N2–SiNx and He–SiNx prepared at 350 °C exhibiting an Ohmic behavior at low fields and a Poole–Frenkel (PF) conduction at high fields. At a deposition temperature of 100 °C the He–SiNx with a dielectric strength of 1.13×107 V/cm and an onset field strength of the PF conduction of 6.9×106 V/cm is in contrast to the N2–SiNx with a dielectric strength of 4.3×106 V/cm and a PF onset field strength of as low as 2×105 V/cm resulting in many orders of magnitude higher current flow. In order to find a correlation between the dielectric and the structural properties of the silicon nitrides several analyses are performed. The He–SiNx proves to be superior to the N2–SiNx concerning refractive index, mass density and buffered HF etch rate at every deposition temperature and the deterioration with decreasing deposition temperature is weaker. All SiNx films are found to be nitrogen-rich at a N:Si ratio of 5:3. As expected, the hydrogen content increases with decreasing deposition temperature, being lower for the He–SiNx than for the N2–SiNx. In all layers most of the hydrogen is bonded to the nitrogen atoms. A simple model is proposed that explains the difference between the two kinds of low-temperature SiNx by the microscopic void structure of the material.

Reverse blocking enhancement of drain field plate in Schottky-drain AlGaN/GaN high-electron mobility transistors

“…At a temperature of 100 • C, the breakdown field can be enhanced from 4.3 MV/cm to 11.3 MV/cm by using He as a dilution gas. [20]…”

1.2.4 Gas-Assisted Focused Ion Beam Fabrication of Gold Nanoelectrode Arrays in Electron-Beam Evaporated Alumina Films for Biosensing Applications

“…the fabrication method does not require high temperature processing. In addition, the Al 2 O 3 films are found to have higher density (3.1 g/cm 3 [8]) than that of plasma-enhanced chemical vapor deposited (PECVD) Si 3 N 4 (2.5 g/cm 3 [9]) which is typically used as the passivation layer for the microelectrodes [10].…”

“…Alumina is deposited at the rate of 3 Å/s until the resulting film thickness of 720 -800 nm is obtained. After the photoresist lift-off process, the substrate is then annealed in air at 300°C for 4 h in order to reduce the density of interfacial traps, thus increase the packing density of the alumina sheath for better insulating properties [9,12]. Fig.…”

Characterization of in situ SiNx thin film grown on AlN/GaN heterostructure by metal-organic chemical vapor deposition

“…It is revealed that the in situ SiN x exhibits a typical silicon nitride behavior. [20][21][22] The curve can be fitted accurately by the combination of an Ohmic conduction mechanism and a Frenkel-Poole emission mechanism, described by…”

“…The Si-rich in situ SiN x in this study contained relatively high concentrations of Si dangling bonds and distorted excess Si-Si bonds, which may result in midgap defect states or bulk traps inducing more electrical conduction by Frenkel-Poole emission. 20,21 Thus, the resistivity and breakdown field can be further improved by optimizing in situ SiN x growth conditions by MOCVD, such as temperature, pressure, and the gas flow of silane and ammonia, by adjusting the N/Si ratio. the presence of a high quality interface between the in situ SiN x layer and the AlN/GaN heterostructure.…”