摘要:

Sharp microtips of silicon have potential applications as field emitters and as electrical or mechanical microsensors. This study describes a single unified etching/oxidation treatment that results in uniform tips with controlled radii of atomic dimensions or larger. Variations in the etching/oxidation treatment form multiple tips with two or four tips per etched pyramid, which offer the possibility of higher emission current density for field emitter applications, and higher sensitivity for microsensor applications.

ISSN:0734-211X    

DOI:10.1116/1.585680

出版商:American Vacuum Society    

年代:1991

数据来源: AIP

摘要:

The dielectric stack of multilevel metal interconnections of integrated circuits contains various forms of dielectrics separating metal conductors. Silicon dioxide deposited by plasma enhanced chemical vapor deposition (PECVD) is one such dielectric. The formation of voids in some of the metal layers stimulated a study of the thermal desorption of H2O from oxide films. The films were deposited by plasma enhanced chemical vapor deposition using a tetraethylorthosilicate precursor. The total amount of H2O desorbed was measured as a function of two deposition variables, deposition substrate temperature, and deposition plasma power. The total amount of H2O desorbed could be reduced by either increasing the deposition substrate temperature or increasing the deposition plasma power.

ISSN:0734-211X    

DOI:10.1116/1.585640

出版商:American Vacuum Society    

年代:1991

数据来源: AIP

摘要:

The effect of Si3N4deposition conditions on the electrical properties of ON dielectric films on smooth and as‐deposited rugged polycrystalline silicon is investigated. The results show that the leakage current, dielectric breakdown strengths, and the charge trapping characteristics of ON dielectric films are influenced by the Si3N4deposition conditions. Larger capacitance increases on rugged electrodes, lower leakage currents, higher breakdown fields, and lower electron trapping rates are observed for ON dielectric films fabricated with low NH3: SiH2Cl2gas ratio and deposited at higher temperature. These films are also expected to have a thicker bottom oxide due to the poor oxidation resistant characteristic of the thin nitride layer deposited at high temperature.

ISSN:0734-211X    

DOI:10.1116/1.585641

出版商:American Vacuum Society    

年代:1991

数据来源: AIP

摘要:

We report in this paper the reactive‐ion etching of WSixfilms using gas mixtures containing NF3. A combination of NF3/H2or NF3/He was used to anisotropically etch WSixfilms as thick as 4000 Å with photoresist masks. They yielded satisfactorily high etch rates and good selectivities with respect to photoresist and III–V materials. The NF3/He mixture yielded higher etch rates for both WSixand photoresist but a lower selectivity with respect to photoresist. CHF3was used with NF3for thicker films and/or submicron features in order to form polymer to protect the sidewalls. Metal masks have to be used in this etch since the etch rates are very low and the selectivity with respect to photoresist is no longer high. A low percentage of NF3and a low pressure were necessary for successful etches using the NF3/CHF3plasma. Etched lines as narrow as 0.18 μm are shown. In addition to the optimal etch conditions, data will also be presented for the effects of variations of cathode coverage, rf power, gas pressure, and gas composition.

ISSN:0734-211X    

DOI:10.1116/1.585637

出版商:American Vacuum Society    

年代:1991

数据来源: AIP

摘要:

The detailed profiles of the wafer charging in different barrel reactor configurations have been obtained by using the electrically erasable–programmable read‐only memory devices. Charging profile in a parallel electrode system depends strongly on the wafer orientation with respect to the rf electric field, while minor changes are observed by the use of floating Al etch tunnel and by the reduction of the wafer‐to‐wafer separation. On the other hand, no wafer charging is detected in a co‐axial electrode system. A simplified equivalent circuit model, which represents the potential in 2‐dimensional rf plasma–wafer system, has been proposed. The charging profile derived from the simplified model coincides with the experimental results. This model gives an analytical explanation of the gate charging.

ISSN:0734-211X    

DOI:10.1116/1.585638

出版商:American Vacuum Society    

年代:1991

数据来源: AIP

摘要:

The use of a filament doping source for Si doping of molecular beam epitaxy (MBE) grown III–V semiconductors provides many benefits in the areas of cleanliness, simplicity of construction, and source lifetime. This work details the thermal and doping characteristics associated with such sources. Expressions are developed for the flux, temperature, and power relations, and for the heating and cooling characteristics. We show that the thermal response allows the doping to be varied by at least two orders of magnitude during the time taken to grow one monolayer at normal growth rates (1 μm/h), and for most applications this obviates the need for a shutter. The source is clean (largely because it is only the strip itself which is at an elevated temperature), repeatable, reliable, has a lifetime comparable with that of the system, and can achieve doping levels of 1019cm−3in GaAs with mobilities of 1300 cm2V−1 s−1at room temperature.

ISSN:0734-211X    

DOI:10.1116/1.585639

出版商:American Vacuum Society    

年代:1991

数据来源: AIP

摘要:

We introduce a method of measuring the surface profile of etched facets on semiconductor lasers, giving direct, quantitative results. Unlike previous techniques which attempt to infer facet quality from electro‐optic performance or subjective analysis of micrographs, this technique provides the actual facet profile. We show how this information can be used for process improvement, and accurate numerical simulation of facet reflectivity.

ISSN:0734-211X    

DOI:10.1116/1.585643

出版商:American Vacuum Society    

年代:1991

数据来源: AIP

摘要:

Using an optical fiber thermometer, wafer temperature was measured during implantation at elevated temperatures. The wafer was mounted on a chuck which was resistively heated to 400 °C. Ar was implanted at an energy of 200 keV and a current in the range of 0–750 μA. Due to poor thermal contact between the chuck and the wafer, wafer temperature could be different from chuck temperature. The wafer temperature varied from ∼300 to 500 °C as a function of implantation current. The wafer temperature was also dependent on the optical properties of the wafer. A model was developed which took the optical properties of the wafer and the chuck into account.

ISSN:0734-211X    

DOI:10.1116/1.585644

出版商:American Vacuum Society    

年代:1991

数据来源: AIP

摘要:

In a projection lithography system having fly‐eye elements, a virtual source is created as an array of approximately mutually incoherent point sources. This paper describes simulated results of the light amplitude and phase of the mask‐projected image for a point source and discusses the dependence on the point source location on a plane situated perpendicular to the optical axis. We showed that the projected image illuminated by point sources far from the optical axis was improved by the effect of interference between multiple apertures. Resolution of the 0.4 μm lines and spaces was improved theoretically and experimentally at a wavelength of 435.8 nm and a numerical aperture of 0.45.

ISSN:0734-211X    

DOI:10.1116/1.585645

出版商:American Vacuum Society    

年代:1991

数据来源: AIP

摘要:

The photoactive and development parameters of commercially availableg‐line photoresists which are TOKs OFPR800, OFPR5000, TSMR8900, and TSMR‐V3, were measured. From the simulated and experimental linewidth linearity data, it was found that the photoactive parameters have very little effect on the resolution power (linearity limit) of photoresists, while the development parameters (dissolution rate characteristics) greatly affect the resolution power. New indices, which can properly characterize the resolution power of photoresists, were extracted from the dissolution rate characteristics curves. One isCd, which is the contrast of the dissolution rate and the other isRd, which is the range of the dissolution rate. These indices are closely related to the resist resolution power. A largerCdorRdgives a higher resolution power to the photoresist. The necessary value ofCd⋅Rdfor the 0.5‐μm feature size photolithography process was derived from experimental data under the present highest NA(=0.55)g‐line stepper for mass production andCd⋅Rdmust be larger than 39. BothCdandRdare useful parameters for estimation of the photoresist resolution power.

ISSN:0734-211X    

DOI:10.1116/1.585646

出版商:American Vacuum Society    

年代:1991

数据来源: AIP