摘要:

Silicon dioxide thick films (1–18 μm) have been deposited at very reasonable deposition rates (20–80 nm/min) with no intentional heating of the substrate (T∼200 °C) using SiH4/O2plasmas coupled in a new type of plasma reactor: The radio frequency plasma excitation used in the helicon diffusion reactor induces the formation of high‐density plasmas (∼1012cm−3) with low plasma potentials. Three main parameters have been investigated; the total gas flow, the oxygen/silane gas flow ratio, and the magnetic confinement in the diffusion chamber. Aninsitucontrol of the refractive index and deposition rate has been obtained and correlated to anexsituanalysis of the deposited films (infrared transmission spectroscopy and chemical etch rate measurements) and the effects of the deposition kinetics on the film properties such as the hydrogen content and the voids fraction have been analyzed.

ISSN:0734-2101    

DOI:10.1116/1.579100

出版商:American Vacuum Society    

年代:1994

数据来源: AIP

摘要:

Epitaxial Si films doped with Er have been grown at low substrate temperatures by plasma enhanced chemical vapor deposition. The Er gas source is a sublimed organometallic compound fed into the process chamber. High doping concentrations without silicide precipitation are possible because of the low deposition temperatures. The process relies on the beneficial effects of low energy ion bombardment to reduce the growth temperature. The ions as well as reactive chemical species are produced by an electron cyclotron resonance plasma stream source. A hydrogen/argon plasma is used to perform aninsitupredeposition clean to remove oxide from the Si surface. Film quality and impurity concentration are determined by Rutherford backscattering spectrometry and secondary ion mass spectrometry.

ISSN:0734-2101    

DOI:10.1116/1.579101

出版商:American Vacuum Society    

年代:1994

数据来源: AIP

摘要:

Optical emission spectroscopy, Langmuir probe, and microwave interferometry measurements have been used to characterize the electron temperature and plasma density of electron‐cyclotron‐resonance (ECR) heated Ar plasmas in a magnetic‐mirror plasma tool. The magnetic field was operated in a symmetric mirror, asymmetric mirror, and minimum‐B configuration. The dependency of the plasma parameters upon microwave power, pressure, and magnetic field configuration have been examined. Plasma densities up to 2×1012cm−3at the midplane and 5×1012cm−3at the ECR zone for a symmetric mirror configuration of the magnetic field have been measured. Operation of the minimum‐B magnetic field configuration was found to increase the plasma stability with comparable plasma density while an asymmetric mirror magnetic field configuration, similar to other devices recently studied, yielded densities in the 2–8×1011cm−3range. Radial uniformity was found to be ±25% over the 4 cm radius of the microwave window.

ISSN:0734-2101    

DOI:10.1116/1.579102

出版商:American Vacuum Society    

年代:1994

数据来源: AIP

摘要:

Planar radio frequency (rf) inductively coupled plasmas (ICP) are currently being investigated as sources for materials processing. We have characterized an Ar plasma ICP discharge using spatially resolved optical emission spectroscopy. Abel inversion of line‐integrated intensities of Ar* emission yields two‐dimensional (r,z) profiles of emission in a cylindrical volume, driven at one end by a spiral antenna with rf power at 13.6 MHz. Measurements were made over a pressure range of 10–100 mTorr, and power levels of 100 and 200 W. In all cases emission intensity was found to peak in a ring‐shaped region at one end of the cylinder adjacent to the location of the antenna, where the rf field is strongest. A local maximum is also observed in most cases near the center of the volume where the electron density peaks [L. J. Mahoney, A. E. Wendt, E. Barrios, and C. J. Richards, J. Appl. Phys.76, 2041 (1994)].

ISSN:0734-2101    

DOI:10.1116/1.579103

出版商:American Vacuum Society    

年代:1994

数据来源: AIP

摘要:

During titanium layer deposition with a hollow cathode arc discharge the integral energy influx to the substrate has been monitored by measuring temperature gradients. Discharge power and substrate voltage have been varied. Simultaneously, the plasma parameters in front of the substrate were determined by means of Langmuir‐probe measurements. From the integral energy influx and the plasma parameters the contributions of the charge carriers and the heat radiation to the substrate heating were calculated. The contribution of the titanium condensation heat could be estimated by means of Rutherford backscattering and ellipsometrical measurements. It was found that heat radiation and charge carriers mainly contribute to the integral substrate heating. The contribution of condensation can be neglected.

ISSN:0734-2101    

DOI:10.1116/1.579104

出版商:American Vacuum Society    

年代:1994

数据来源: AIP

摘要:

We have established a dry process based on molecular beam epitaxy (MBE) of organic molecules under ultrahigh vacuum (UHV) condition on a clean and bare silicon surface. We designed a new MBE system suited to depositing organic materials based on the Monte Carlo simulation of the molecular motion. Cu phthalocyanine thin films were prepared with the system as a test. Films with high flatness and crystallinity without contamination were prepared on the substrates prepared by the UV/HF method developed earlier in our research group. The possibility of controlling the crystal structure of the deposited thin film by the surface crystallinity of the substrate is suggested based on the observation on differently prepared substrate surfaces.

ISSN:0734-2101    

DOI:10.1116/1.578974

出版商:American Vacuum Society    

年代:1994

数据来源: AIP

摘要:

This article describes a compact growth system specifically designed for metalorganic molecular‐beam epitaxy (MOMBE) of InP‐based materials. The system is designed to take full advantage of the MOMBE method, in particular the premixing of the group III and V precursors, respectively, and the elimination of large solid effusion cells. The system uses a fixed sample heating stage which is designed for indium wafer mounting, up to a 2 in. diameter, on molybdenum blocks. Temperature control during growth is done with a thermocouple inserted directly into the sample block with a small charge of indium to provide intimate thermal contact. Sample loading is done vertically from above in order to load the sample in the growth position. The system is controlled by a personal computer, which also replaces all of the analog temperature and pressure controllers. Initial results on 2‐in. diameter wafers indicate excellent uniformity of the composition, Δa/a=±2×10−4for InGaAs, and photoluminescence, ±4.5 nm for InGaAsP, respectively. In addition, high‐speed InGaAs/InP heterostructure bipolar transistors and charge injection transistors grown in this system have demonstratedfT’s of 125 and 73 GHz, respectively.

ISSN:0734-2101    

DOI:10.1116/1.578975

出版商:American Vacuum Society    

年代:1994

数据来源: AIP

摘要:

A low energy electron gun to provide a uniform electron flux at an extended target surface has been designed, built, and tested. The simple and unique configuration of the electron gun combined with its low energy, high current, and uniform electron flux properties make it suitable for electron‐stimulated desorption studies on extended surfaces requiring uniform bombardment over centimeter dimensions.

ISSN:0734-2101    

DOI:10.1116/1.578976

出版商:American Vacuum Society    

年代:1994

数据来源: AIP

摘要:

Hollow cylindrical fusion targets of 200–300 μm diam and 500–600 μm length, were fabricated and fitted at one end with a metallic ablator plate. The cylinders were then filled with a solution of polyfunctional acrylate monomer, which was subsequently polymerized to a gel using ultraviolet initiated polymerization. Either one or two aluminum spheres of diameter between 10 and 30 μm were placed in the gel at defined locations, before the gel was precipitated to give, on drying by critical point dryer, a foam of the required density (about 100 mg cm−3). The final targets had the sphere or spheres embedded in the foam at specified locations. Several techniques for placing the spheres were examined and the relative merits of the techniques are discussed.

ISSN:0734-2101    

DOI:10.1116/1.578977

出版商:American Vacuum Society    

年代:1994

数据来源: AIP

摘要:

Basic material studies addressing the growth and processing of CdTe have resulted in dense, defect‐free as‐grown CdTe films on 7059 glass with initial grain sizes of ≊0.2 μm. Innovations in postdeposition processing (no CdCl2) have resulted in films with ≳50 μm grain sizes. Scanning electron microscopy analyses confirm film density while concurrent cathodluminescence reveals a change in the recombination efficiency. Transmission electron microscopy analyses reveal that films grown below 300 °C are defect‐free, while films grown above 300 °C contain defects. Photoluminescence lifetime measurements reveal a fivefold increase in lifetime following postdeposition processing of these films. These results were correlated with x‐ray photoemission measurements of the Te 4d, Cd 4d, and valence band. This indicates that grain boundaries are the main factor limiting lifetimes. Based on these results, we have developed an understanding of the effects of oxygen and grain boundary oxides on postdeposition processing and enhanced grain growth.

ISSN:0734-2101    

DOI:10.1116/1.578947

出版商:American Vacuum Society    

年代:1994

数据来源: AIP