摘要:

The properties of silicon nitride film obtained by plasma‐assisted chemical vapor deposition (plasma CVD) are studied along with the effect of NH3plasma treatment on plasma CVD silicon nitride/silicon interface characteristics. With this NH3plasma treatment of the silicon surface before silicon nitride film deposition, the interface state densities of the silicon nitride/silicon interface are reduced to about 1010cm−2 eV−1and the hysteresis voltage of the capacitance–voltage (C–V) curve is reduced to 0.1 V. These improvements are most pronounced when there is a large H concentration in the silicon nitride film. However, no effect is observed when N2or H2plasma was used instead of NH3plasma. Auger electron spectroscopy analysis of the silicon surface after NH3plasma treatment shows that nitrogen is incorporated in the near surface region of the silicon substrate. This implies that nitridation of the silicon surface occurs due to NH3plasma treatment and the interface characteristics are improved because the silicon nitride/silicon interface is made inside the silicon substrate due to this nitridation.

ISSN:0734-211X    

DOI:10.1116/1.584349

出版商:American Vacuum Society    

年代:1988

数据来源: AIP

摘要:

We describe an improvement in optical pyrometry of GaAs substrates, by restricting the pyrometer wavelength to a band of 0.91 to 0.97 μm. This allows temperature measurement of nonbonded GaAs wafers during molecular‐beam epitaxial growth, without interference from the radiation emitted by the substrate heater. Error‐free readings have been obtained for substrate temperatures as low as 440 °C, which is particularly important for the automated growth of alloys such as (In,Ga)As. By detecting a larger substrate surface area and using a calibration curve, the useful measurement range can be extended even lower.

ISSN:0734-211X    

DOI:10.1116/1.584351

出版商:American Vacuum Society    

年代:1988

数据来源: AIP

摘要:

We have developed a process using molecular‐beam epitaxy for growing GaAs/AlGaAs quantum wells with thicknesses and Al content that vary in a controlled manner on (100)‐oriented GaAs substrates. The control is accomplished by manipulating the Ga sticking coefficient through local variations of the substrate temperature. To indicate the range of thickness and Al content variations that can be achieved, we show that exciton peak energies of the quantum wells can be made to vary as much as 200 meV between predetermined locations<2 mm apart on the wafer. The quality of the exciton spectra is good throughout, indicating good quality epitaxial layers throughout. This process allows flexibility in designing the well dimensions and composition in various regions of the wafer and could lead to a variety of important developments in GaAs devices.

ISSN:0734-211X    

DOI:10.1116/1.584307

出版商:American Vacuum Society    

年代:1988

数据来源: AIP

摘要:

Patterned doping of GaAs using a thin solid Si dopant source by pulsed excimer laser melting is described. Linewidths as narrow as 0.3 μm are demonstrated. The power‐dependent linewidth of the doped region agrees well with calculations of transient heat conduction in the substrate.

ISSN:0734-211X    

DOI:10.1116/1.584308

出版商:American Vacuum Society    

年代:1988

数据来源: AIP

摘要:

A new model for the analysis of resist heating is proposed and applied to the direct electron beam writing method using a variably‐shaped electron beam system and a single‐layer resist. From calculations based on the present model and experiment, it was found that the resist heating effect leads to resist ablation, difference in resist sensitivity between single exposure and multiple exposures, and depth dependence and beam size dependence of resist sensitivity. It also explains the degradation of shaped beam stitching accuracy as well as pattern size error. The resist heating effect is more serious for direct writing than the estimation obtained from a conventional model. In order to realize submicron patterns below 0.5 μm with considerable high throughput, the use of a highly sensitive resist is essential for overcoming the resist heating effect.

ISSN:0734-211X    

DOI:10.1116/1.584309

出版商:American Vacuum Society    

年代:1988

数据来源: AIP

摘要:

The effect of ambient atmospheric conditions during x‐ray exposure on the sensitivity of a new type positive resist, which contains poly(2‐methylpentene‐1‐sulfone) as the radiation‐sensitive compound, is studied. Resist sensitivity to x rays is seen to depend strongly on oxygen pressure during exposure. Sensitivity in air is only one‐sixth of that in a vacuum. Using Fourier transform infrared spectral analysis of the resist film following x‐ray irradiation, it is found that the alkyl radical of poly(2‐methylpentene‐1‐sulfone) generated by x‐ray irradiation is easily scavenged by the oxygen molecule in air, thus retarding its further unzipping decomposition.

ISSN:0734-211X    

DOI:10.1116/1.584310

出版商:American Vacuum Society    

年代:1988

数据来源: AIP

摘要:

Calculated image intensity profiles (IIP’s) are presented for contact holes printed with partial coherence levels in theS=0.5 toS=0.7 range and are compared to IIP’s of the correspondingly dimensioned line–space gratings. Improvements in the depth of focus (DOF) latitude and resolution at higher coherence levels (lower pupil fillS) are quantified for contact hole projection lithography with high‐numerical aperture (NA),g‐line lenses. The relationship between contact and grating DOF is quite complex and changes with the coherence level. Higher pupil fills produce greater differences between the contact and grating DOF. Workable contact hole resolution levels for 0.7, 0.6, and 0.5 pupil fills are estimated to occur atkfactors of 0.89, 0.83, and 0.79, respectively, where thekfactor normalizes feature size to the resolution factor λ/NA of the lens.

ISSN:0734-211X    

DOI:10.1116/1.584311

出版商:American Vacuum Society    

年代:1988

数据来源: AIP

摘要:

A pattern dimension determination method has been developed. The three parameters, linewidth, wall angle, and film thickness represent pattern dimension. The total waveform of a measured backscattered electron signal is compared with a standard signal data base. Two methods are adopted to reduce data base construction time. (1) The data base was constructed with Monte Carlo simulation by a supercomputer. (2) Data base size is reduced using a waveform approximation method. The two improvements result in fast data base construction (26 min) for a specified material sample. This data base construction method is more practical than preparing signal data base from real standard sample due to data base construction time. Obtained dimensional accuracies are found to be 0.02 μm, 5 deg, and 0.1 μm for linewidth, wall angle, and film thickness, respectively, with scanning electron micrograph comparisons. Deduction time for obtaining physical dimensions from a signal was 17 s.

ISSN:0734-211X    

DOI:10.1116/1.584312

出版商:American Vacuum Society    

年代:1988

数据来源: AIP

摘要:

Registration marks for electron lithography are usually detected by scanning with an electron beam and measuring the backscattered electron (BE) signal. If the registration mark is on the axis of the lithography tool, the BE signal is symmetric and the mark position may be found accurately. Practical electron lithography often requires that registration marks be found off axis, for example, near the edges of an exposure field. In this case, it is shown by both experiment and Monte Carlo calculation that the registration signals become asymmetric which causes registration errors. It is also shown that these errors can be reduced by a suitable choice of BE detector shape and position.

ISSN:0734-211X    

DOI:10.1116/1.584313

出版商:American Vacuum Society    

年代:1988

数据来源: AIP

摘要:

Chlorine (Cl2) reactive ion beam etching (RIBE)‐induced damage on the GaAs wafer has been characterized by studing the characteristics of Schottky diodes fabricated on the etched surfaces. The ideality factors and the Schottky barrier heights measured by the current–voltage characteristics for ion extraction voltage range from 30 to 200 V at Cl2gas pressure of 2×10−3Torr and are comparable to those of the reference sample cleaned by HCl. Both thenvalue and the barrier height degrade for ion extraction voltage of more than 300 V. For higher Cl2gas pressure, the damage on the etched surface is less. These results suggest that with the low‐energy ions and high‐Cl2gas pressure, the damage of the GaAs surface is reduced significantly. The electron deep levels induced by RIBE disappear after annealing at 400 °C for 10 min.

ISSN:0734-211X    

DOI:10.1116/1.584314

出版商:American Vacuum Society    

年代:1988

数据来源: AIP