Sputtering-type Electron Cyclotron Resonance Research Articles

Electrical properties of low-temperature epitaxial doped Si thinfilms fabricated by using a sputtering-type electron cyclotron resonanceplasma

The electrical properties of Sb-doped n+ epitaxial Si filmshave been investigated. These films were fabricated at low temperatures ofbelow 515 °C and at a conventional base pressure of 5×10-7 Torr using a sputtering-type electron cyclotron resonance plasma.It was found that the Sb dopants in the target were almost whollyincorporated into lattice sites of epilayers and the Hall mobility of theepilayers grown at 515 °C was comparable to that of the bulk Si. Areverse current density as low as 1×10-8 A cm-2 wasobtained by a direct deposition of an n+ epilayer on a p-typesubstrate, which suggests the formation of a high-quality interfacebetween the epilayer and the substrate. The precise control of thedeposition gas pressure, substrate potential and substrate temperature wasfound to be very important for the fabrication of high-quality epilayers.Heavily B-doped p+ epilayers were also fabricated at a substratetemperature of 515 °C. The B dopant was wholly incorporated intothe epitaxial layers, but annealing at temperatures of more than700 °C was required to electrically activate the B dopant. Theelectrical activation mechanism has been discussed and it has beeninferred that the B dopant occupied interstitial sites in the as-grownepilayers.

Electrical characteristics of p–n junction diodes fabricated by Si epitaxy at low temperature using sputtering-type electron cyclotron resonance plasma

This article reports the electrical characteristics of p–n junction diodes that were formed by directly depositing a Sb-doped n-type epilayer on a p-type substrate by using a dc-bias electron cyclotron resonance plasma sputtering system at a low temperature of 400 °C and a conventional vacuum of 5×10−7 Torr. The reverse current density of the n+–p junctions diodes depends on deposition gas pressures and substrate biases. The n+–p junction diodes exhibit, under optimum conditions, a reverse current density as low as 9.5×10−9 A/cm2 at a reverse bias voltage of 5 V and an ideality factor of 1.05. The excellent characteristics of the n+–p junction diode are due to the integrity of interface between n+ epilayer and p-type Si substrate.

In situ Fourier transform P-polarized infrared reflection absorption spectroscopic investigation of an interface properties of SiO 2/Si(100) deposited using electron cyclotron resonance microwave plasma at room temperature

Amorphous SiO 2 films have been deposited onto the Si substrate, without heating, using sputtering-type electron cyclotron resonance (ECR) microwave plasma. In situ Fourier transform P-polarized infrared reflection absorption spectroscopy (ISFT-PIRRAS) has been used to study the properties of a-SiO 2/Si interface. The results from ISFT-PIRRAS monitoring indicated that the interface stress led to significant distortion in the local structure, which resulted in the broadening of a transverse optical mode (TO 3) located at 1050 cm −1. The interface stress decreased with increased film thickness. In addition, the longitudinal optical phonon mode (LO 3, located at 1223 cm −1) related to TO 3 mode was observed due to Berreman effect [B. Harbecke, Appl. Phys. A: Solids Surf. 38 (1985) 263]. This phonon mode is very sensitive to SiO 2 film thickness, which enables it to be used to detect and characterize ultra thin SiO 2 film. When the film thickness is over 30 nm, a non-linear dependence of the intensity of LO 3 mode on film thickness was observed. However, the TO 3 mode has a near linear dependence on film thickness. Thus, it is more accurate and suitable to detect thick film by monitoring TO 3 mode intensity.

Study of the effects of discharge conditions and substrate temperature on Si epitaxial deposition using sputtering-type electron cyclotron resonance plasma

It was found that epitaxial Si films could be deposited on Si substrates by using a sputtering-type electron cyclotron resonance plasma that had a conventional base pressure of 5×10−7 Torr. The effects of discharge conditions and substrate temperature were studied systematically in order to understand the necessary conditions for epitaxial growth. It was found that discharge gas pressure, target power for sputtering, and substrate temperature play crucial roles in the epitaxial deposition. The implications of the changes of the three parameters are discussed in detail.

Room Temperature Deposition of Silicon Nitride Films for Passivation of Organic Electroluminescence Device Using a Sputtering-Type Electron Cyclotron Resonance Plasma

Dense silicon nitride (SiN) films were deposited at room temperature by a sputtering technique using an electron cyclotron resonance (ECR) plasma. Film properties were studied using ellipsometry, chemical etching, Fourier transform infrared spectroscopy, and thermal desorption spectroscopy. A SiN film deposited under the optimum condition of nitrogen gas flow rate had a refractive index of 2.03 and showed a large Si–N bond number. The SiN film had a high barrier against moisture penetration relative to SiN films prepared by chemical vapor deposition at 900°C. This indicates that the film deposited using a sputtering-type ECR plasma has the potential to be utilized as a passivation layer of devices such as organic electroluminescence, which require low temperature processing.

Room Temperature Deposition of Silicon Oxynitride Films with Low Stress Using Sputtering-Type Electron Cyclotron Resonance Plasmas

AbstractSilicon oxynitride (SiOxNy) films with low stress were deposited successfully at room temperature using sputtering-type electron cyclotron resonance (ECR) plasmas. Films were deposited for a wide range of flow rate ratio of O2 to N2 at a constant Ar flow rate. Film properties were verified by characterizations of refractive index (ellipsometry), structural properties (Fourier transform infrared and Auger electron spectroscopy), intrinsic stress, and barrier strength of water penetration (thermal desorption spectroscopy). A near-stoichiometric SiOxNy (x = 1.44 and y = 0.41) film with low stress could be formed at the optimum deposition condition, under which the SiOxNy film had a refractive index of 1.54. The results of thermal desorption spectroscopy measurements showed that the SiOx Ny film had a higher barrier against moisture penetration relative to deposited SiOx and SiNy films. The SiOxNy film was directly deposited on the organic EL device and the applicability was shown clearly. These results indicate that this SiOxNy film deposited using a sputtering-type ECR plasma has the potential to be utilized as a passivation layer of organic EL devices, which are required to be formed at low temperature.

Compositional and structural studies of amorphous silicon-nitrogen alloys deposited at room temperature using a sputtering-type electron cyclotron resonance microwave plasma

Abstract High-quality amorphous silicon-nitrogen alloys (a-SiN x ) have been deposited at room temperature by a sputtering-type electron cyclotron resonance (ECR) plasma. A detailed analysis of the properties of a-SiNx films in terms of their composition, microstructure and dielectric characteristics was performed using X-ray photoelectron spectroscopy, infrared (IR) spectroscopy and ramp current-voltage measurement techniques. Their characteristics were correlated with the N2 gas flow rate (NGFR) in the ECR plasma formation. The dependence of solid-state [N]/[Si] ratios in the films on the NGFR indicated that the film composition changed from non-stoichiometry to stoichiometry as the NGFR increased from 0.5 to 1 seem. The dependence of the IR spectra on the NGFR indicated that silicon nitride network was well ordered for an NGFR of 1 seem, in which the dielectric breakdown-field was over 4 MVcm−1. However, when the NGFR was over 1 seem, significant N≡N triple bonds (gaseous N2 molecule) were formed ...

Compositional and structural studies of amorphous silicon-nitrogen alloys deposited at room temperature using a sputtering-type electron cyclotron resonance microwave plasma

Compositional and structural studies of amorphous silicon-nitrogen alloys deposited at room temperature using a sputtering-type electron cyclotron resonance microwave plasma

Effects of oxygen content on properties of silicon oxide films prepared at room temperature by sputtering-type electron cyclotron resonance plasma

We present the study of the effects of gas-phase oxygen fraction on properties of silicon oxide films prepared in a sputtering-type electron cyclotron resonance plasma discharge. Dielectric breakdown characteristics of the films are considerably improved by an increase in oxygen flow rate, FO2, with a constant Ar gas flow rate of 16 sccm. Films prepared at FO2 of more than 6 sccm have good dielectric breakdown fields of 9–11 MV/cm, which are comparable with those of high quality thermally grown SiO2. Moreover, the increase of FO2 improved structural properties of the films. Detailed measurements of their composition and microstructure were carried out using ellipsometry, chemical etch rate measurement in a mixture of HF, H2O, and HNO3 (P etch), x-ray photoelectron spectroscopy (XPS), and infrared (IR) spectroscopy techniques. Ellipsometry and XPS measurements indicated that films prepared at FO2 of more than 3 sccm are stoichiometric. Dependence of the IR spectra and P etch rate on FO2 of more than 3 sccm indicated that distribution of Si–O–Si bond angle and Si–O bond strain in the films decreases with an increase of FO2. Based on the behavior of the Si–O–Si bond angle and refractive index of the films, we discuss the improvements in structural properties in terms of growth kinetics.

Observation of Si cluster formation in SiO2 films through annealing process using x-ray photoelectron spectroscopy and infrared techniques

SiO 2 films having high breakdown characteristics were deposited by a sputtering-type electron cyclotron resonance microwave plasma at room temperature. As-deposited films were annealed in an Ar ambient at temperatures ranging from 450 to 1000 °C. Transmitted infrared (IR) absorption and x-ray photoelectron spectroscopy (XPS) were used to characterize the as-deposited and annealed films. XPS measurements indicated that the as-deposited films had an approximately stoichiometric composition containing a few intermediate SiOx(x≠2) species and Ar atoms around some dangling-bond defects. The dependence of XPS spectra on annealing temperature showed that steep diffusion of the Ar atoms occurs at annealing temperatures of 450–550 °C and the SiOx species separate into SiO2 phase and Si clusters by an annealing process of 750–950 °C. Based on the full width at half-maximum variations of Si 2p XPS spectra and Si–O stretching mode of IR spectra for the annealed films, we discuss the Si cluster formation in SiO2 films through the annealing process.

In situ FT-IR reflective absorption spectroscopy for characterization of SiO 2 thin films deposited using sputtering-type electron cyclotron resonance microwave plasma

Plasma conditions for depositing high quality SiO 2 thin films using a sputtering-type ECR (electron cyclotron resonance) method have been investigated. Film properties have been studied as a function of an oxygen flow rate, F O 2 , in the range 2–8 sccm with a constant Ar flow rate of 16 sccm. Dielectric breakdown characteristics have been investigated by ramp I- V measurements, indicating that the film prepared with F O 2 = 8 sccm to the thickness of 412 Å have a good dielectric breakdown field of 8–10 MV/cm. The deposited films were characterized in terms of refractive index and IR (infra-red) properties using FT-IRRAS (Fourier transform infrared reflective absorption spectroscopy) and ellipsometry. The refractive index of films deposited with more than F O 2 = 3 sccm is close to 1.46 which indicates that the films prepared in this range are approximately stoichiometric. In addition, quantitative analysis of the dominant IR (infra-red) mode shows that the peak frequency and FWHM (full width at half-maximum) of a TO (transverse optical phonon) mode for films prepared with more than F O 2 = 6 sccm are comparable with thermally grown SiO 2, i.e. v = 1075 cm −1 and FWHM = 70 cm −1. These observations indicate the optimum operating condition of the sputtering-type ECR apparatus, at which it can produce high quality films for MOS (metal-oxide semiconductor) device manufacture without the need for substrate heating.

In-situ infrared reflective absorption spectroscopy characterization of SiN films deposited using sputtering-type ECR microwave plasma

High quality amorphous silicon nitride films have been deposited, without substrate heating, using a sputtering-type electron cyclotron resonance (ECR) microwave plasma. The compositional and structural characterizations have been made by means of a Fourier transform infrared (FT-IR) spectrometer and an ellipsometer. The correlation between the microstructure of a-Si x N y films and nitrogen gas fraction relative to argon ( N 2 Ar ) is discussed. In-situ Fourier transform infrared reflection absorption spectroscopy (ISFT-IRRAS) has been used to study the properties of a-Si x N y Si interface. The results from ISFT-IRRAS monitoring indicate that the broadening of a SiN stretching vibration mode, induced by interface stress, decreases with increased film thickness.

Low-temperature deposition of high-quality silicon dioxide films by sputtering-type electron cyclotron resonance plasma

High-quality silicon dioxide films have been deposited at 130 °C by a sputtering technique using an electron cyclotron resonance microwave plasma. Film properties have been studied as a function of O2 flow rate in the range of 2–8 sccm with a constant Ar flow rate of 8 sccm when other plasma conditions were a microwave power of 700 W, and a radio frequency power of 700 W supplied to a target for sputtering. Dielectric breakdown characteristics have been investigated by ramp current–voltage measurements. Films deposited with an O2 flow rate of 5.3 sccm have a dielectric breakdown field of 10 MV/cm, which is close to that of thermally grown silicon dioxide film. The deposition rate was as high as 23 nm/min. Structural properties of films have also been characterized by ellipsometry and infrared absorption spectroscopy, showing that films with O2 flow rates above 4 sccm have near-stoichiometric composition.

Crystal structures and optical properties of ZnO films prepared by sputtering-type electron cyclotron resonance microwave plasma

This paper describes the crystal structure and photochromism of Zn oxide films fabricated by sputtering-type electron cyclotron resonance microwave plasma. C-plane preferential orientation and (101) plane preferential orientation are achieved in Zn oxide films deposited on glass substrates below 200 °C. These films have strong crystallite orientation. Films with (101) plane orientation exhibit typical photochromic characteristics induced by x-ray irradiation. Photochromism is probably caused by a color center, that is, the oxygen vacancy in Zn oxide films. The absorption center exists in an energy range of 1.5 to 4 eV. The activation energy in the fading process is ∼0.03 eV.

A new sputtering-type electron cyclotron resonance microwave plasma using an electric mirror and high-rate deposition

Film deposition is performed by means of a new electron cyclotron resonance microwave plasma employing a high-rate sputtering system using an electric mirror. This apparatus consists of both planar and cylindrical targets. The magnetic flux penetrates both target surfaces. Microwave power is perpendicularly or obliquely introduced into the resonance cavity. High-density plasma, exceeding 1012 cm−3, much denser than the cutoff density 7×1010 cm−3, is generated. The electron beam oscillating between the two targets plays a major role in generating the dense plasma, i.e., as a beam plasma interaction. Both insulator and conductor films can be deposited continuously by this new sputtering method at high rates under low gas pressures of 10−2 . Al, Mo, and Fe films are deposited at rates above 2000 Å/min. Target utility reaches higher than 55% for nonmagnetic materials including Mo and Al, and 40% for magnetic materials including Fe. Film thickness uniformity over 4 in. in diameter with a 10% distribution is realized.

New high-rate sputtering-type electron cyclotron resonance microwave plasma using an electric mirror

High-rate sputtering is achieved by means of new electron cyclotron resonance microwave plasma employing sputtering using an electric mirror. This apparatus consists of both planar and cylindrical targets. Microwave power is perpendicularly or obliquely introduced into the resonance chamber. High-density plasma of 1012 cm−3 is generated. The reflected electrons oscillating between the two targets play a major role in generating the dense plasma, i.e., as a beam-plasma interaction. Both insulator and conductor films can be continuously deposited by this sputtering method at high rates under low gas pressures of 10−2 Pa. Al, Mo, and Fe films are deposited at rates above 2000 Å/min.

Photochromism and anomalous crystallite orientation of ZnO films prepared by a sputtering-type electron cyclotron resonance microwave plasma

This letter describes the crystal structure and the photochromism of ZnO films, which are prepared by a sputtering-type electron cyclotron resonance microwave plasma. c-axis preferential orientation and (101) preferential orientation are realized in the Zn oxide films, which are deposited on a glass substrate at a low temperature below 200 °C. Both films have an excellent crystallite orientation that is the best reported to date. The films with anomalous crystallite orientation exhibit typical photochromic characteristics, which are induced by x-ray irradiation. The photochromism is caused by a color center, that is, the O2− vacancy in ZnO films. The absorption center exists in an energy range of 1.5–4 eV.

Characteristics for Sputtering Type Electron Cyclotron Resonance Microwave Plasma and Its Applications to Thin Film Preparations

Characteristics for Sputtering Type Electron Cyclotron Resonance Microwave Plasma and Its Applications to Thin Film Preparations