We discuss the gate electrode effects on SiO2 degradation in MOS structures. The gate electrode material was poly‐silicon, but the impurity doping procedure was varied in terms of species and concentrations. First, the origin of the substrate hole current observed in n‐MOSFETs, by injecting electrons from the silicon substrate, is discussed in terms of oxide thickness and gate electrode doping species, because the dielectric breakdown is closely related to the total hole fluence in the oxide. The effects of the gate electrode on the oxide network structure and on the Si/SiO2 interface are also experimentally investigated. Finally, the experimental results obtained for Qbd of different gate electrode MOSFETs are shown, including the polarity dependence of Qbd. Furthermore, the percolation analysis to explain the polarity dependence is introduced, since the dielectric breakdown process is really stochastic.

We briefly review the controversy concerning the proper methodology for the assignment of soft x‐ray photoemission Si 2p core levels at Si/SiO2 interfaces. Evidence for Second nearest neighbor effects in the photoemission spectra of analogous free molecules in the gas phase are surveyed for the purpose of placing this controversy within a wider context. Physisorption experiments have been performed to inquire whether the second nearest neighbor effects found in free molecules are in any way reduced in their magnitude owing to the proximity to the highly polarizable Si surface. No evidence for such a diminution have been found.

Annealing effects have been investigated for the SiO2 films deposited from a Tetra‐Iso‐Cyanate‐Silane and Tertiary‐Alkyl‐Amine gas mixture in order to stabilize its desirable hydrogen‐free property. It was found that O3 annealing eliminates effectively the NCO‐group from the deposited film, resulting in the improved water resistance characteristics, and that HF changes the Si‐NCO bonds to Si‐F bonds resulting also in improved film properties.

We have performed electron spin resonance and electrical measurements on SiO2/Si structures subjected to anneals in 5% H2/N2 or 5% D2/N2 gases and subsequently injected with electrons using corona ions and ultra‐violet radiation. Threshold voltage and transconductance measurements have also been made on 0.25 μm metal‐oxide‐semiconductor transistors subjected to 400 °C anneals in the same gases and subsequently aged by hot electron injection. The electrical data on SiO2/Si structures indicates that the density of interface states increases as a result of electron injection but that there are only minor differences between H and D passivated interfaces. The data on Pb, trivalent Si dangling bond, centers at the same interfaces observed by electron spin resonance is insufficiently accurate to enable us to observe any significant differences. The hot electron injection experiments on transistors, consistent with other authors, indicate that, for the limited number of measurements we have made, the transistor ageing resulting from the generation of interface states is significantly reduced for devices annealed in the D containing gas as compared to those annealed in the H containing gas. The origins of some potential differences in annealing behaviour between the SiO2/Si structures and the 0.25 μm transistors are suggested.

A remote plasma enhanced chemical vapour deposition (RPECVD) process was used to deposit thin silicon dioxides on silicon substrates. The oxide properties were compared with thermal oxides with similar thicknesses (2.5–9 nm) using capacitance‐voltage (C‐V), current‐voltage (I‐V) and constant voltage stress measurements (I‐t). Post‐metallization annealing (PMA) showed different annealing dynamics as compared to the thermal oxides for anneal times below approximately 1000 s (at 260 °C) after which the dynamics were similar. The deposited oxides had a higher initial interface state density (Dit) than the thermal oxides, but after PMA they were found to be of the same quality as the thermal oxides. Positive charging of the deposited oxides during constant voltage stress was the same as for thermal oxides, showing that the stress endurance of the two are similar.

This paper focuses on establishing a baseline for thin dielectric processes including: low temperature, dilute, stacked (TEOS), oxynitride, and high temperature annealed (grow‐anneal‐grow) oxidation. 105Å (total thickness) gate dielectrics were grown or deposited for this study. The stack oxide showed the highest Vbd yields for both large‐area and edge‐intensive capacitors, but the poorest Qbd. The N2O oxide yielded mediocre Vbd and Qbd. The low temperature and dilute oxides showed early breakdowns, but acceptable Qbd. 900°C thermal gate oxide showed slightly better average Vbd than low temperature and dilute oxides but comparable Qbd. The high temperature annealed oxide appears to have the best electrical performance, but the worst uniformity.

A molecular dynamics computer simulation of amorphous SiO2 has been made to investigate the structure and dynamics. The effects of the external stresses on the amorphous structure were investigated through the radial distribution function, the distribution of Si‐O‐Si bond angles, and the distribution of coordination numbers.

The sub‐initial oxidation of Si (111) surface by a high‐flux pure ozone was investigated using X‐ray photoelectron spectroscopy. In addition to the advantage of the pure ozone which can efficiently oxidize the Si surface at room temperature, the high‐flux ozone was found to further enhance the oxidation. The possibility of producing negative ions of oxidizing gases using Rydberg electron transfer was also investigated.

A solution to the thin film silicon transistor gate metallization problem in active matrix liquid crystal displays is demonstrated in the form of a self-passivation process for copper. Bottom-level copper (Cu) lines are passivated by a self-aligned CrOx encapsulation formed by surface segregation of chromium (Cr) from dilute Cu1-xCrx alloys (x=0.1–2.3) at 400°C. The encapsulation is an efficient barrier for Cu diffusion into the SiNx gate insulator during the plasma deposition and transistor processing, and solves the problems of oxidation and adhesion to the glass substrate. Gate line resistivities are 4.5 to 7.5μΩcm depending on the initial Cr concentration. The performance of self-passivated Cu-gate thin film transistors is comparable to that of transistors with refractory metal gates.

The research in this paper is based on an approach to low‐temperature/low‐thermal budget device fabrication that combines plasma and rapid thermal processing, and which has been customized to control separately: (i) the N‐atom bonding chemistry and composition profiles, and (ii) the structural and chemical relaxations necessary for device‐quality performance and reliability for stacked gate structures. Control of N‐atom incorporation at the monolayer level at the crystalline‐Si and polycrystalline‐Si interfaces of field effect transistors, and at alloy levels within the bulk dielectrics has been achieved by combining low‐temperature (∼300°C) plasma‐assisted processes to generate the N‐atom concentration profiles, with low‐thermal‐budget rapid thermal annealing (RTA) to promote chemical and structural relaxations that minimize defects and defect precursors.

We discuss the electrical and photo-electrical properties of monolayers of long hydrocarbon chains (alkyltrichlorosilane molecules) self-assembled on a silicon substrate. It is shown that these monolayers (<3 nm thick) act as high quality insulators : DC conductivity through the monolayers are in the 10-15 S/cm range, energy barrier heights at the silicon/monolayer interface are in the 45 eV range. Chemical surface modifications of these monolayers are reported in order to tailor their surface as well as electrical (dielectric constant) properties. Possible sub-01 μηι device applications are presented.

The electrical properties and the hot-carrier reliability of P+ poly-gate P-MOSFET's are investigated for advanced 0.35 μπι LDD CMOS technologies. It is shown that surface-channel p-devices with an optimized plasma NH3 nitrided gate-oxide have good barrier properties and electrical performances which lead to a higher hot-carrier immunity in 8nm thick nitrided gate-oxides than in pure oxides using DC and AC experiments. The AC stressing shows that reducing the gate-oxide thickness leads to a larger influence of electron detrapping inducing a stronger influence of donor type interface traps than the usual build-up of negative charges. These distinct degradation mechanisms are less significant in nitrided oxide p-MOSFET's due to the lower lateral electric field leading to a lower amount of trapped charges which are quickly suppressed during subsequent detrapping phases leaving the main influence of the interface traps.

Amorphous thin films of a typical side-chain nonlinear optical polymer were investigated by means of dielectric spectroscopy and thermally stimulated depolarization current (TSDC) within the temperature range -40°C to 230°C. Three distinct relaxation processes, labelled α, β and γ were observed. The α-relaxation, associated with the glass transition, is well described by the Vogel-Fulcher relation, while the sub glass transition β and γ-relaxation follow Arrhenius relations. The advantage of TSDC over dielectric spectroscopy is demonstrated for the investigation of the weak β-relaxation in the side-chain polymer. Furthermore, the β -relaxation is responsible for the initial, fast decay of the electro-optical response of the side-chain polymer at room temperature.

During a high RF power (60–100 W) N20/He remote plasma oxidation of Si(100) at 300 °C, nitrogen atoms have been incorporated at the top surface of an ultra-thin (1.0–2.5 nm) oxide. Online Auger electron spectroscopy (AES) has been used to estimate the dielectric film thickness and track the evolution of the film growth. A chemically shifted Si-LW feature from the high RF power oxidation sample indicates that the nitrogen is bonded to the silicon at the top surface of the oxide film. The stability of the bonded nitrogen is also evident in the persistence of the N-KLL Auger peak following (i) a 30 s rapid thermal anneal (RTA) in Ar at 900 °C and (ii) a remotely excited He plasma treatment at 300 °C for 15 s.

Silicon nitride (SiNx) films have been successfully synthesized by the catalytic chemical vapor deposition (cat-CVD) method using a gaseous mixture of silane (SiH4) and ammonia (NH3). In the method, the deposition gases are decomposed by catalytic cracking reactions with a high temperature (1700°C) catalyzer near the substrates, and SiNx films can be deposited at substrate temperatures lower than 400°C without using plasma or photochemical excitation. Nearly stoichiometric Si3N4 films are formed when the flow ratio of NH3 exceeds over 100 times of that of SiH4. These cat-CVD SiNx films show excellent properties. That is, the resistivity, the breakdown voltage, the chemical etch resistance and hydrogen content in the films are almost equivalent to those of high-temperature thermal CVD films. In addition, the surface diffusion length of depositing species is about several-tens μπι and step-coverage itself is conformai. Thus, the cat-CVD SiNx films are regarded not only as a new device passivation films superior to the conventional plasma-CVD films but as a gate insulator for electon devices due to their high quality.

This study describes the use of fluorinated silicon nitride film as a bottom antireflective layer (BARL) material suitable for line-patterning in quarter-micron KrF excimer laser lithography. For the structures of photoresist/BARL (300Å)/c-Si and photoresist/BARL (300 Å )/W-Si at a wavelength of 248nm, 0% reflectance could be achieved when the refractive index (n) and extinction coefficient (k) values of the film are 2.11 and 0.68 or 2.05 and 0.59, respectively. The fluorinated silicon nitride thin films on p-type (100) Si substrates obtained by inductively coupled plasma enhanced CVD have been evaluated with the variations of NF3 flow rates under the two conditions of SiH4:N2=2:15 and 3:20 (seem). The films optical constants and reflectance were investigated by spectroscopic ellipsometry combined with a reflectance simulation program. The film n and k values at 248nm vary in the ranges of 1.67~2.35 and 0.01~0.69, respectively, depending on gas flow ratio of SiH4:N2:NF3. Low reflectance of below 5% can be obtained from reflectance simulation for two deposition conditions with a BARL thickness of 300Å. In addition, the reflectance could be reduced to almost 0% by controlling film thickness. Finally, the antireflective layer performance was investigated using KrF excimer laser lithography.

A statistically designed experiment was run to optimize the deposition of PECVD SiN on GaAs substrates. Five deposition parameters were varied: RF power, temperature, pressure, plasma frequency, and ammonia/silane ratio. Four film properties were used to evaluate the quality of the nitride: the fraction of hydrogen bound to nitrogen atoms, the index of refraction (and its uniformity), thickness uniformity, and stress. From the screening phase of the experiment, it was determined that only the plasma frequency and ammonia/silane ratio influenced the quality of the nitride film. High frequency deposition was preferable to low frequency deposition since it resulted in lower film stress. The results of the optimization phase showed that SiN films with near‐zero stress, low N‐H bond density and good index of refraction could be obtained by deposition at a very low ammonia/silane ratio.

Oxidation stability of silicon oxynitride is a property of great technological significance. In this study, the oxidation behavior of stoichiometric polycrystalline Si2N2O was investigated in 1 and 0.5 atm flowing dry oxygen at 1000°‐1300°C. The oxidized Si2N2O samples were characterized using transmission and scanning electron microscopy. The oxidation kinetics were determined using profilometry in conjunction with patterned etching. Oxidation of Si2N2O resulted in the formation of amorphous SiO2. The SiO2‐Si2N2O interface was chemically and structurally abrupt. A parabolic rate law was followed during oxidation with apparent activation energies ranging from 43 to 52 kcal/mol. The relatively high activation energy values compared to that for silicon oxidation suggest that oxidation of Si2N2O is rate‐controlled by a more complex process than molecular oxygen diffusion in amorphous SiO2.

The electrical properties of oxynitride films on strained SiGe grown and deposited, respectively, using a N2O and a combination of N2O and hexamethyldisilazane (HMDS) plasma are reported. X-ray photoelectron spectroscopy (XPS) analysis of the N2O grown films have shown the incorporation of N at the oxide interface without any Ge segregation. The hole confinement in accumulation in SiGe/Si heterostructure with 90 Å N2O oxynitride film has been observed by C-V measurements. Plasma reoxidation of N2O grown dielectric films has resulted in significant improvement of electrical properties. Oxynitride films deposited using PECVD of HMDS have shown comparatively inferior properties. Films deposited from a mixture of N2O and HMDS, exhibit the highest value of Dit (1x1012 cm-2eV-1), probably due to higher amount of nitrogen incorporation at the interface. The charge trapping behavior of both the grown and deposited films have been studied. The effect of addition of NH3 in HMDS plasma and N2O oxidation prior to HMDS PECVD on the charge trapping behavior has been studied.

Silicon nitride thin films are deposited at low temperature using the inductively coupled plasma enhanced chemical vapor deposition.(ICP‐CVD) N2 and SiH4 gases are used as reactant gases for deposition of silicon nitride thin films with low hydrogen content. Composition, refractive index, and hydrogen content of the films were examined with variation of N2 flow rate, RF power and substrate temperature. As N2 flow rate and RF power increase and substrate temperature is lowered, N/Si ratio is reduced producing higher refractive index of the film. Hydrogen content of the films is calculated by FTIR spectroscopy and is much less than those of the films deposited by conventional PECVD using SiH4/N2 gases since N2 gas is used instead of NH3 gas. Total hydrogen content is constant regardless of RF Power and N2 flow rate. However, the hydrogen content decreases with increasing substrate temperature due to the release of hydrogen at high temperature.