摘要:

Palladium gated metal–insulator–semiconductor diodes are efficient and sensitive detectors for low‐energy hydrogen ions. Environments which contain fluxes of hydrogen ions, like fusion reactors, may also contain fluxes of ionizing radiation. The effect of ionizing radiation in vacuum and various atmospheres on our diodes is reported. In general, irradiation in vacuum produces little permanent damage in our diodes and will not give signals which will be confused with the signals from hydrogen ions. Irradiation in air for some kinds of diodes produces metastable interface states.

ISSN:0734-211X    

DOI:10.1116/1.584061

出版商:American Vacuum Society    

年代:1988

数据来源: AIP

摘要:

The principles governing the plasma deposition of SiO2films for use as gate insulators ina‐Si thin‐film transistors (TFT’s) are discussed. A deposition arrangement is described which favors the reaction at the substrate over that in the discharge volume. It is shown that the variables leading to large values of the breakdown fieldEbkand to greatest stability of the flat band voltageVfbare the substrate temperatureTs, the gas flow ratio N2O/SiH4, and the ratio of the discharge half‐period to the transit time of the ions between the electrodes.a‐Si/SiO2TFT’s operated in the dc mode and in a mode simulating LC display operation show much less shift of the threshold voltageVththan doa‐Si/Si3N4TFT’s for equivalent gate fields.

ISSN:0734-211X    

DOI:10.1116/1.584062

出版商:American Vacuum Society    

年代:1988

数据来源: AIP

摘要:

The properties of low‐hydrogen, fluorinated plasma‐enhanced chemical vapor deposition (PECVD) silicon nitride films grown using NF3/SiH4/N2feed mixtures in 200 kHz and 14 MHz discharges were compared. High‐energy ion bombardment at 200 kHz is expected to enhance surface diffusion and chemical reconstruction. Compared to fluorinated silicon nitride deposited at 14 MHz under otherwise comparable conditions, the 200 kHz films had a lower Si–H bond concentration (≲1×1021cm−3), lower total hydrogen content (5–8×1021cm−3), better resistance to oxidation, lower compressive stress (−0.7 to −1.5 Gdyne/cm), and higher density (3.1 g/cm3). The dielectric constant of better low‐frequency Class I films was constant to 500 MHz, while that of high‐frequency films fell up to 15% between 100 Hz and 10 MHz. The absorption edges of low‐frequency PECVD fluorinated silicon nitride films were between 5.0 and 6.1 eV, which compare with 4.4 to 5.6 eV for the high‐excitation frequency fluorinated material and 3 to 4 eV for conventional PECVD nitride. However high‐frequency films may have fewer trap centers and a lower dielectric constant. 14 MHzp‐SiN:F films grown with NH3as an auxiliary nitrogen source showed absorption edges similar to low‐frequency material grown from NF3/SiH4/N2, but they have substantially more N–H bonding. The dielectric constant and absorption edge of these films were comparable to those of low‐frequencyp‐SiN:F from NF3/SiH4/N2.

ISSN:0734-211X    

DOI:10.1116/1.584063

出版商:American Vacuum Society    

年代:1988

数据来源: AIP

摘要:

A new method for fabricating ultrafine grooves with a high depth to width ratio is proposed. The main feature of this method is to use V‐shaped SiO2grooves as etching masks. These grooves are prepared by depositing a SiO2film onto the patterned substrate employing electron cyclotron resonance (ECR) plasma deposition, followed by removing the sidewall deposited ECR‐SiO2films with buffered HF solution. The gap width formed at the bottom of the V grooves were controlled by varying the HF etching time. Fine grooves having 0.2 μm or narrower widths were successfully fabricated into Si substrates and Ta films. Suppressing the localized undercutting is vital for fabrication of nanometer scale structures.

ISSN:0734-211X    

DOI:10.1116/1.584064

出版商:American Vacuum Society    

年代:1988

数据来源: AIP

摘要:

Fused glass which is used as an insulation layer in the electrical packaging of integrated circuits can be precisely patterned by etching with pulsed, ultraviolet laser radiation. The glass absorbs weakly at both 193 and 248 nm lines of the excimer laser. Etching by 193 nm pulses (∼20 ns FWHM) begins at a threshold fluence of 0.5 J/cm2and rises to 1200 Å/pulse at ∼2.5 J/cm2. The etch depth increases linearly with the number of pulses and the tolerance achieved is better than 5 μm. The etched holes are well‐defined in outline. Etching by 248 nm pulses has a threshold fluence of ∼1.2 J/cm2. The etched pattern is irregular and shows damage due to shattering that is well outside the irradiated area. The etch depth is difficult to control since the surface that is produced is uneven. The maximum etch depth per pulse that was realized was only 150 Å. The etching by 193 nm laser pulses is believed to depend on the creation of color centers which strongly increases the absorption cross section.

ISSN:0734-211X    

DOI:10.1116/1.584065

出版商:American Vacuum Society    

年代:1988

数据来源: AIP

摘要:

A two‐dimensional microtopography etch simulation using Monte Carlo methods is presented. This simulation investigates the topography of an arbitrary profile, periodic semiconductor surface after (ion assisted) plasma etching. The dependence of the topography on the etch chemistry, the ion energy, and the physical bombardment mechanism is discussed. For sputter etching, the degree of anisotropy is shown to be related to both the ion directionality and the sputter yield function. The potential for using this simulation to analyze microscopic properties of plasma etching is discussed.

ISSN:0734-211X    

DOI:10.1116/1.584066

出版商:American Vacuum Society    

年代:1988

数据来源: AIP

摘要:

Basic chemical processes involved in etching of silicon nitride with a CF4/O2radio frequency plasma have been investigated using optical emission spectroscopy. Spectra have been recorded in the range 2400–7050 Å and comparison has been made of the intensity of more than 60 atomic and molecular lines in the presence and absence of silicon nitride coated wafers. We identify a number of species as important etching agents including metastable F(4P), CF2, and metastable F+(1D,1S). Our results are consistent with the principle of spin conservation in surface reactions set out in earlier work on Si(100). Our conclusions extend and broadly confirm the results of a previous mass spectrometric study of the same system.

ISSN:0734-211X    

DOI:10.1116/1.584398

出版商:American Vacuum Society    

年代:1988

数据来源: AIP

摘要:

A new process of excimer laser lithography is presented in this paper. A water soluble, contrast enhancing material, we have developed for the KrF (248 nm) excimer laser has made this new process possible. This material, named WSP‐EX (water soluble photopolymer for excimer laser), is characterized by the use of 5‐diazo‐Meldrum’s acid and has good contrast enhancing capability in both photobleaching and photoreactive speed at 248 nm. By utilizing this new material, we can obtain large focus‐depth lattitude. In this paper, the problem of matching the contrast enhancing material with the resist is also discussed.

ISSN:0734-211X    

DOI:10.1116/1.584399

出版商:American Vacuum Society    

年代:1988

数据来源: AIP

摘要:

Simultaneous bleaching of a contrast enhancing film (CEF) and the underlying positive photoresist is considered in the absence of any interface or substrate reflectivity. The intensity transmitted by the CEF is determined as a function of exposure time exactly using the absorptivity of the film in Dill’s model equations. Corresponding to this time dependent transmitted intensity, the concentration profiles in the positive photoresist have been expressed exactly in closed form. Relations, that implicitly define the developed image profile, are derived assuming that the resist development can be approximated by a two state process. Furthermore, they are solved numerically for a polysilane–AZ2400 resist system and a model CEM‐388–resist combination proposed by Mack. The predicted image profiles are in excellent agreement with the experimentally determined profiles of Hoferetal., for the polysilanes, and the predictions ofprolithfor the model system of Mack.

ISSN:0734-211X    

DOI:10.1116/1.584400

出版商:American Vacuum Society    

年代:1988

数据来源: AIP

摘要:

The influence of As+ion implantation on the oxidation of TiSi2films was investigated. It is shown that implantation of As leads to a greatly increased rate of oxidation in a dry O2ambient. Oxidation of a silicide implanted with inert Ar+ions showed that the effect is not solely due to ion‐induced damage but depends on the presence of As in the film. The microstructure of these films, before and after oxidation, was studied using high‐resolution transmission electron microscopy and Rutherford backscattering. Also, the morphology of As+‐implanted films after rapid thermal annealing will be discussed. Under certain conditions, the morphology is substantially affected by the implant.

ISSN:0734-211X    

DOI:10.1116/1.584401

出版商:American Vacuum Society    

年代:1988

数据来源: AIP