摘要:

Surface reflection Raman scattering has been used to examine interfacial chemical reactions which occur at the Al–GaSb interface during thermal aging. The chemical composition of the interfacial layer has been determined and reactions have been identified at temperatures as low as 300 °C. Under thermal aging conditions where the Al overlayer is not fully reacted, the primary reaction product is AlSb. Depletion of the aluminum overlayer followed by continued reaction leads to an interdiffused layer of AlxGa1−xSb which exhibits a concentration gradient normal to the interface. Both amorphous and crystalline AlSb have been identified depending on the thermal aging conditions.

ISSN:1071-1023    

DOI:10.1116/1.583557

出版商:American Vacuum Society    

年代:1986

数据来源: AIP

摘要:

Reaction of single‐crystal GaAs with molecular chlorine was studied with and without simultaneous bombardment by energetic argon ions. The reaction was detected by aninsitumass spectrometer; reflected chlorine and reaction product signals were measured as functions of crystal temperature. A modulated molecular beam of intensity 1×1017cm−2 s−1was used for the purely thermal reaction tests. At temperatures greater than 550 K, the monochlorides of Ga and As were observed in equal quantities. At lower temperatures, only the trichlorides were observed. A maximum reaction probability for trichloride production of 0.3 was observed at 450 K. The effect of modulated ion bombardment with a steady Cl2beam was also examined. The shapes of the waveforms of the desorbed products observed in this experiment suggested that the gallium‐chloride‐producing reaction was stimulated by ion bombardment. In the absence of ion‐assisted desorption, the gallium chloride surface builds up to a saturation coverage of ∼1015Ga atoms/cm2. This layer prevents reaction of the substrate GaAs with the Cl2beam. A quantitative model of the ion‐assisted reaction was proposed and compared with the data.

ISSN:1071-1023    

DOI:10.1116/1.583558

出版商:American Vacuum Society    

年代:1986

数据来源: AIP

摘要:

Silicon surfaces after Ar ion‐assisted etching in Cl2gas atmosphere were studied for various Ar ion current densities and Cl2gas pressures. The number of incident Ar ions was varied in 6×1014–3×1016ions/cm2/s while the number of incident Cl2molecules was varied in 0–3×1017molecules/cm2/s. Ar ion acceleration energy was fixed at 1 keV. High etching rate, about 5000 Å/min, was observed with a high incident rate of both Ar ions and Cl2molecules. On the other hand, high etch yield was observed at low incident rate of Ar ions and high incident rate of Cl2molecules. The amount of surface defects and surface chemical adsorption states, which vary with different etching conditions, were studied by etch pit observation after thermal oxidation followed by Secco‐etching, x‐ray photoelectron spectroscopy (XPS), and reflection high energy electron diffraction (RHEED). Silicon surfaces, etched under high etch yield etching conditions, showed relatively high Si2O3existence by XPS measurement, and high density etch pits. It is considered to be related with high density surface defects and roughness. Etch pits did not appear after conventional wet cleaning process. It is caused by a little surface oxidation and relatively less Si2O3existence than other kinds of oxides on the surface.

ISSN:1071-1023    

DOI:10.1116/1.583516

出版商:American Vacuum Society    

年代:1986

数据来源: AIP

摘要:

The concentration and distribution of chlorine incorporated into silicon substrates during reactive ion beam etching is investigated. Rutherford backscattering spectrometry and Auger sputter profiling are employed to analyze the single crystal silicon samples. Data are presented for samples etched at various energies, current densities, and angles of incidence. The effect of temperature, dopant concentration, and crystalline orientation are also discussed. The amount of chlorine retained by the substrate decreases sharply with increasing energy and temperature. The quantity of chlorine retained increases linearly with current density, and is insensitive to doping level and orientation. Chlorine incorporation increases with angle of incidence asA/cos (bθ), where θ is measured with respect to the surface normal. Samples etched at low energies show surface roughening and thick oxide growth. The data are in large part accounted for by a combination of direct and recoil implantation. However it is argued that radiation enhanced diffusion is responsible for results obtained at high current densities and large angles to the beam. Implications for reactive ion etching are discussed.

ISSN:1071-1023    

DOI:10.1116/1.583517

出版商:American Vacuum Society    

年代:1986

数据来源: AIP

摘要:

Bias electron cyclotron resonance (ECR) plasma deposition technology is proposed to planarize submicron interconnections with a high aspect ratio (height/space of interconnection) in which rf bias is applied to the substrate of the ECR plasma deposition system. The technology has the following advantages. First, the concave region of the narrow gap between submicron interconnections with a high aspect ratio above 1.0 can be planarized and formed at the same insulator thickness as that of the convex region. This is due to high directionality of ECR plasma particles. Second, both deposition and etching rates can be controlled by adjusting the gas flow rates as well as the rf and microwave power. Third, an rf bias can be applied from the initial stage of the planarization process. This is because of sputter‐etching with O2ions without Ar, thus enabling a shorter planarization time. Using the bias‐ECR plasma deposition technology, the 0.5 μm line/space Al (0.5 μm thickness) interconnection surface can be perfectly planarized.

ISSN:1071-1023    

DOI:10.1116/1.583518

出版商:American Vacuum Society    

年代:1986

数据来源: AIP

摘要:

In the anisotropic dry etching of conductive films deposited on topographic steps, it is difficult to remove the residue even with extended overetch. The resistances of the residues from aluminum and silicide etching are found not to depend on film thickness or step coverage but to depend on bias voltage and pressure. The etch profiles observed by SEM are discussed in terms of native oxide film and polymer film formation. A simple model is proposed to reveal the residue formation process and to explain the problem encountered during the removal of the etched residue. A simple method is presented to determine the minimum requirement of a reliable etch process associated with surface topology.

ISSN:1071-1023    

DOI:10.1116/1.583519

出版商:American Vacuum Society    

年代:1986

数据来源: AIP

摘要:

Geometrical features of an alignment mark for focused ion beam (FIB) implantation in GaAs with precise alignment were studied. To optimize the etched shape on a GaAs wafer, intensity profiles of secondary electrons emitted by scanning the FIB across the mark were calculated from Monte Carlo simulation of implanted ion trajectories. The contrast and sharpness of the intensity profiles at the mark relate to the inclination angle of its sidewall and the etched depth. It was confirmed that the calculated results agreed with the experimental ones. For irradiation of 160‐keV‐Si FIB on the alignment mark with an 85° inclination angle, its etched depth of 2  μm gives the maximum contrast and sharpness. Under this condition, Si was implanted in the designated region with an alignment accuracy of 0.1 μm.

ISSN:1071-1023    

DOI:10.1116/1.583520

出版商:American Vacuum Society    

年代:1986

数据来源: AIP

摘要:

A new metallization process was developed. Grooves and holes with an aspect ratio of up to 1 were completely filled and partially planarized by the combination of high vacuum evaporation and sputter etching in a multiple cycle alternating process. Excellent agreement between experimental and computer simulated groove and hole profiles was achieved.

ISSN:1071-1023    

DOI:10.1116/1.583521

出版商:American Vacuum Society    

年代:1986

数据来源: AIP

摘要:

Modifications have been made on a contact‐resistance‐monitor (CRM) process which permit measurements to be made immediately after metal deposition, i.e., without photolithographic metal patterning. The modified or prepatterned CRM has been calibrated versus the standard CRM, and shown to have equal sensitivity to sputter‐deposition system cleanliness. The sensitivity of the CRM method for monitoring system cleanliness has been shown to be approximately the cube of the sensitivity of residual‐gas‐analyzer methods.

ISSN:1071-1023    

DOI:10.1116/1.583522

出版商:American Vacuum Society    

年代:1986

数据来源: AIP

摘要:

A molybdenum silicide (Mo‐silicide) film deposited on a quartz glass substrate offers major advantages as a high performance photomask material for very large scale integrated (VLSI) fabrication. There is no pattern missing due to exfoliation after ultrasonic cleaning with frequency of 28 kHz and 300 W of power, and after being scrubbed over 10 cycles with a high pressure water jet. Reflectivity and optical density of the Mo‐silicide film are not affected by acidic chemicals. Moreover, dry etching can be done at a rate of 50 nm/min; more than five times as fast as etching of a chromium (Cr) mask.

ISSN:1071-1023    

DOI:10.1116/1.583523

出版商:American Vacuum Society    

年代:1986

数据来源: AIP