摘要:

A concise review of the basic ideas of the generalized kinematic model of surface evolution during growth and erosion is presented. Interpretation of the main results of this model as well as some specific rules and advice as to how this model is applied in practical simulations are also presented. It is concluded that three‐dimensional (3D) computer simulation of surface evolution is only possible by the use of adequate, theoretically motivated numerical methods. As a demonstration, 3D topography simulations during broad and focused ion beam bombardment, chemical vapor deposition, and reactive ion etching using the 3D codedineseare also presented.

ISSN:0734-2101    

DOI:10.1116/1.578859

出版商:American Vacuum Society    

年代:1994

数据来源: AIP

摘要:

A multipolar electron cyclotron resonance (ECR) plasma source was characterized by Langmuir probe measurements and the charged particle energy and density are related to photoresist etch rate. Ion density was found to increase with microwave power but decrease with source distance, and is independent of rf power and flow rate. Among the different gases investigated, Ar plasma was found to have higher ion density compared to O2, N2, and Cl2discharge. Ion density peaked at 5 mTorr for Ar and 2 mTorr for O2plasma. For a N2plasma, the maximum ion density was found to occur at 10 mTorr at 3 cm and 2 mTorr at 23 cm below the ECR source. Electron temperature is ∼3 eV for pressure ranging from 1 to 5 mTorr but decreases to 2 eV at 20 mTorr. Photoresist etch rate follows the same trend as ion density. It increases with microwave power and decreases with source distance. On the other hand, photoresist etch rate increases with rf power and flow rate, even though the ion density remains constant. This suggests that photoresist etching also depends on ion energy and concentrations of neutral species. Ion density uniformity of ±1% for a N2plasma was measured across the central 24 cm along the stage at 23 cm below the source. For a source distance between 3 and 23 cm, uniformity of ±3% was obtained over a 12 cm diam region on the stage. In an O2plasma, photoresist etch rate uniformity of ±2% was measured for a 10 cm diam wafer and the corresponding ion density uniformity was ±1%.

ISSN:0734-2101    

DOI:10.1116/1.578860

出版商:American Vacuum Society    

年代:1994

数据来源: AIP

摘要:

The reactive ion etching (RIE) of GaAs, AlGaAs, InP, InGaAs, InGaAsP in Cl2/BCl3/Ar or CCl2F2/BCl3/Ar discharges is investigated as a function of the plasma parameters: power, pressure, and relative composition as well as etching time. For the reason of In‐based fluoride with high boiling point, the etching rates of all of these materials are faster in Cl2/BCl3/Ar in comparison to CCl2F2/BCl3/Ar. The In‐based compounds show a similar dependence on power density and discharge composition, but it is quite different from GaAs. When discharges containing CCl2F2are used, the surface morphologies are quite rough after the treatment of RIE with either type of discharge, although smooth etching surfaces can be obtained under appropriate conditions. Using BCl3containing gas discharges will enhance smooth surface and maintain high etching rate. For selective etching of GaAs on AlGaAs, gas mixtures containing CCl2F2are used. High performance and high selective etching can be obtained by using CCl2F2/BCl3/Ar gases mixtures. Photoresist or SiO2were used as etching masks. Silicon dioxide is better than the photoresist mask for its low etching rate and sputtering to III–V compounds, and it could beinsituremoved by CF4plasma. The photoluminescence measurements show high performance of etched results when the power density was maintained at less than 0.6 W/cm2.

ISSN:0734-2101    

DOI:10.1116/1.578861

出版商:American Vacuum Society    

年代:1994

数据来源: AIP

摘要:

TiN films were deposited onto various substrates including InP by rf sputtering in an N2/Ar ambient at room temperature. The rf power, the ratio of gas flows, and the total pressure were systematically varied. To optimize the deposition conditions, the plasma excitation processes were examined by optical emission spectroscopy using a calibrated crystal thickness monitor to determine the corresponding deposition rates. At pressures below 15×10−3mbar, the deposition rate is linearly proportional to the intensity of the optical emission at 364.2 nm,I(Ti), associated with excited Ti. AlthoughI(Ti) increases with the total pressure, at a given rf power, the resulting deposition rate decreases at pressures above 20×10−3mbar due to greater gas‐phase scattering. The [N]/[Ti]ratio in the deposited films, as determined by Rutherford backscattering and Auger electron spectroscopy, is found to be linearly correlated with the ratio of the optical emission intensities of excited N+2(391.4 nm) and Ti at 364.2 nm,I(N+2)/I(Ti).

ISSN:0734-2101    

DOI:10.1116/1.578863

出版商:American Vacuum Society    

年代:1994

数据来源: AIP

摘要:

A study of the growth ofa‐SiC:H films by plasma‐enhanced chemical vapor deposition (PECVD) from two organosilicon precursors, silacyclobutane (H2CH2SiCH2CH2or SCB) and methylsilane (CH3SiH3), is described. A capacitively coupled, parallel plate PECVD system was used to grow films at 250 °C and deposition pressure of 2.0 Torr. Standard (13.56 MHz) and low frequency (0.125 MHz) rf sources were used to generate the deposition plasma. Depositions were performed with and without argon dilution (neat) of the precursor. We report some of the first process/property relationships for organosilicon baseda‐SiC:H films grown using a fixed, controlled set of deposition conditions. Included are data on film composition, structure, dielectric constant and stress. Films deposited from silacyclobutane had much higher carbon concentrations than those deposited from methylsilane, but in both cases the carbon fraction in the film was lower than that in the precursor. It is found that the plasma drive frequency has a stronger influence on film composition than argon dilution of the precursor during deposition. The low frequency plasma significantly increases the film growth rate for the neat precursor process. Depending on the growth process, the relative dielectric constants of thea‐SiC:H films ranged from 3.6 to 8.7. The variation of the dielectric constant over the frequency range 0.1–1000 kHz was negligible. All measured film stress was compressive and ranged from 0.1 to 1.0 GPa depending on precursor and plasma frequency. Films deposited from a 10% organosilicon/90% argon mixture showed higher dielectric constants, higher refractive indices and less bound hydrogen when compared to neat organosilicon precursor depositions. The films exhibited excellent oxidation resistance and could not be etched in 6:1 buffered HF solutions. The properties of thea‐SiC:H films are compared to PECVD hydrogenated silicon nitride and discussed in the context of applications requiring low temperature deposited protective dielectric coatings.  

ISSN:0734-2101    

DOI:10.1116/1.578864

出版商:American Vacuum Society    

年代:1994

数据来源: AIP

摘要:

A radio frequency excited helicon plasma is generated by coupling externally generated electric and magnetic fields into the plasma confined by an axial magnetic field. The 13.56 MHz rf power provided via an antenna is varied between 100 and 500 W. The axial magnetic field strength is varied between 25 and 150 G. The substrate electrode is independently powered with 13.56 MHz radio frequency. A 100 μm orifice in the substrate electrode allows a small sample of argon ions bombarding the substrate electrode to enter a detection chamber. In the detection chamber a quadrupole mass spectrometer equipped with an energy filter is used to measure mass selected ion energy distributions and by tilting the quadrupole analyzer with the vertex lying in the orifice ion angular distributions are investigated. The ion energy distributions at the powered electrode mainly consist of either a single peak or they consist of the well known bimodal structure caused by rf splitting. For some source parameter a continuous energy distribution is detected for lower bombardment energies, which is interpreted as the result of scattering of ions with the background gas during their transport to the substrate electrode. The variation of the total flux intensities, the dc bias potentials, and the plasma potentials are evaluated and are interpreted as a result of mode transitions of the helicon plasma. The ion angular distributions are unstructured and show angular widths in the range between 2° and 3° full width at half‐maximum. Some aspects concerning the application of the source for semiconductor etching processes are discussed.  

ISSN:0734-2101    

DOI:10.1116/1.578865

出版商:American Vacuum Society    

年代:1994

数据来源: AIP

摘要:

A new source of metastable argon atoms in the thermal energy range is reported. The source is based on expanding a plasma sustained by electromagnetic surface waves in a quartz tube through a converging nozzle and extracting a beam from the supersonic free‐expansion jet. The beam was characterized by time‐of‐flight measurements which yielded the absolute intensity and velocity distribution of the argon metastables. The source produced a maximum intensity of 6.2×1014metastables per second per steradian, the highest time‐averaged intensity of thermal argon metastables of any source reported to date. A simple picture of an expanding plasma in a recombination regime is used to explain the dependence of the metastable intensity on absorbed power.

ISSN:0734-2101    

DOI:10.1116/1.578903

出版商:American Vacuum Society    

年代:1994

数据来源: AIP

摘要:

We have constructed a chemical vapor deposition/etching system consisting of a 2.45 GHz microwave generator (ASTeX S‐1000) and two movable coaxial magnetic coils. A unique rotatable planar Langmuir probe was designed to characterize the plasma. The Langmuir probe measurements showed an anisotropic character of the plasma which was mainly a result of the magnetic field gradient and propagation direction of the microwaves. By placing the coils at certain distances from the microwave window and adjusting the current through the coils, a critical condition was established, known as ‘‘high mode plasma.’’ In this high mode, the plasma ion density was more than four times that in the normal mode. The physical basis of the high mode involved placing the electron cyclotron resonance critical field (875 G) just in front of the microwave window with a positive magnetic field gradient toward the direction of microwave propagation. This condition produced a high absorption of microwave power and also prevented charged particles from escaping from the plasma.

ISSN:0734-2101    

DOI:10.1116/1.578904

出版商:American Vacuum Society    

年代:1994

数据来源: AIP

摘要:

Deposition of gallium oxide and indium oxide on GaAs (001) was investigated by the alternating supply of triethylgallium (TEGa) or trimethylindium (TMIn), and hydrogen peroxide (H2O2). A pressure‐control method was newly developed to produce precisely controlled surge pulses of source gases. Strong temperature dependence of the growth rate per source cycle obtained for the oxide deposition was caused by the decomposition of metalorganics, and by the thermal desorption of the oxide during the deposition. A critical thickness of 20 nm for the thermal desorption of gallium oxide was observed, which gives the upper limit of the promotive effect of underlying GaAs on thermal desorption of gallium oxide. With implications forinsituprocess use, deposition of GaAs on gallium oxides and on indium oxides was performed by chemical beam epitaxy, and the differences between the two oxides were discussed from the viewpoint of gallium‐atom‐induced desorption and selectivity for GaAs deposition.

ISSN:0734-2101    

DOI:10.1116/1.578905

出版商:American Vacuum Society    

年代:1994

数据来源: AIP

摘要:

Growth of layered NbSe2has been carried out on a GaAs (111)B surface by molecular beam epitaxy (MBE). The optimum growth conditions to obtain high quality films were investigated by use of reflection high energy electron diffraction. Single crystalline films as thick as 100 nm were obtained when suitable surface treatment of the GaAs substrate was made with the interruption of the Nb beam or the use of a cracked Se beam. The factors determining the MBE growth of layered NbSe2are also discussed.  

ISSN:0734-2101    

DOI:10.1116/1.578906

出版商:American Vacuum Society    

年代:1994

数据来源: AIP