摘要:

We present data on interface characteristics ofSi3N4/Si/GaAsmetal–insulator–semiconductor (MIS) structures and correlate electrical properties with spectroscopic ellipsometry, x-ray photoelectron spectroscopy (XPS), and transmission electron microscopy (TEM) observations. The interface ofSi3N4/Si/GaAsheterostructures was electrically characterized by a combination of capacitance–voltage and conductance methods. The nature of an insulator/GaAs interface and the microstructure ofSi3N4/Si/GaAsinterfaces after high temperature annealing were investigated by variable angle spectroscopic ellipsometry and high resolution TEM, respectively. The evolution of chemical species inSi3N4/Si/GaAsheterostructures was examined usingin situangle-resolved XPS. The interface trap density(Dit)of theSi3N4/SiMIS capacitor was in the2×1010 eV−1 cm−2range near the Si midgap after rapid thermal annealing at 550 °C inN2.However, this density increased to high1010 eV−1 cm−2with annealing at 800 °C. The interface characteristics ofSi3N4/Si/GaAsstructures withDitin the7×1010 eV−1 cm−2range also degraded after annealing at 750 °C inN2withDitincreasing to5×1011 eV−1 cm−2near the GaAs midgap. The spectroscopic ellipsometry results together with high resolution TEM observations appear to suggest that the degradation is due in part to the interface changing from crystalline to amorphous through chemical reaction. XPS measurements revealed that the as-deposited Si interlayer is nitridated during the initial stages of silicon nitride deposition, thus the thinned Si cannot prevent the outdiffusion of Ga and As species. We circumvented thermally induced interface degradation ofSi3N4/Si/GaAsstructures by employing a novelex situ/in situgrowth approach.

ISSN:1071-1023    

DOI:10.1116/1.590338

出版商:American Vacuum Society    

年代:1998

数据来源: AIP

摘要:

Oxygen contamination has been observed inIn0.5Ga0.5Pand(Al0.23Ga0.77)0.5In0.5Pfilms grown by solid source molecular beam epitaxy with elemental phosphorus. Using a conventionalP4cracking zone temperature of 950 °C, spike contamination levels as high as1×1019 cm−3were observed at growth interrupted interfaces with the resultant deactivation of silicon doping pulses. By reducing the phosphorus cracking temperature to 700 °C, the oxygen level in InGaP was reduced to below the secondary ion mass spectrometry background level of3×1016 cm−3.No measurable accumulation of oxygen was observed at growth interrupted interfaces and efficient silicon pulse doping was obtained. InGaP films grown at the lower cracking temperature exhibited improved mobilities and enhanced photoluminescence intensities. An oxygen level in(Al0.23Ga0.77)0.5In0.5Pof less than1.5×1017 cm−3was obtained with good mobilities and luminescence. Efficient silicon pulse doping in AlGaInP was demonstrated. The oxygen contamination is in the phosphorus flux and is likely a volatile phosphorus oxide such asP4O6.

ISSN:1071-1023    

DOI:10.1116/1.590339

出版商:American Vacuum Society    

年代:1998

数据来源: AIP

摘要:

The composition and chemical state of the native oxide of single-crystalline ZnSe and the effect of HCl(18.5%)/H2Owet etching have been studied by time of flight secondary ion mass spectrometry (TOF-SIMS) and x-ray photoelectron spectroscopy (XPS). TOF-SIMS depth profile measurements show that the oxide layer of ZnSe is removed by etching in this solution for one minute, followed by a subsequent one minute rinse in deionizedH2O.XPS depth profile measurements of the untreated ZnSe surface show that Se oxide only exists at the topmost surface (within the top 10% of the oxide layer). The change of Zn Auger parameter with depth of the untreated ZnSe specimen indicates that the remaining oxygen is chemically associated to Zn. High resolution XPS measurements of the etched ZnSe show no detectable Se oxide at the surface. Meanwhile, the Zn Auger parameter is similar to that of the unetched ZnSe after its oxide layer being removed byAr+sputtering. Both experiments show longer wet etching times result in Zn deficiency and more Cl contamination at the sample surface.

ISSN:1071-1023    

DOI:10.1116/1.590340

出版商:American Vacuum Society    

年代:1998

数据来源: AIP

摘要:

A method was examined for evaluating the electrical conductivity of a photoresist to predict its development speed. The conductivity of organic solutions of the photoresist base polymer at various frequencies was found to have a positive correlation with the dissolution speed of the photoresist base polymer into an alkaline developer. In addition, the influence of the measurement temperature and of the concentration of the polymer solution on the conductivity was investigated. It is shown that a prediction of development speed of a photoresist by measuring its conductivity is possible.

ISSN:1071-1023    

DOI:10.1116/1.590341

出版商:American Vacuum Society    

年代:1998

数据来源: AIP

摘要:

The properties of both oxygen indiffusion and oxidation resistance in aTa+RuO2layer for high density memory devices were investigated by using Rutherford backscattering spectroscopy, four point probe, x-ray diffraction, x-ray photoelectron spectroscopy, and planar transmission electron microscopy. TheTa+RuO2/Sisystem sustained up to 800 °C without an increase in resistivity. TheTa+RuO2diffusion barrier showed a Ta amorphous microstructure and an embeddedRuOxnanocrystalline structure in the as-deposited state. TheTa+RuO2film showed the formation ofRuO2phase by reaction with the indiffused oxygen from atmosphere after annealing in an air ambient. TheTa+RuO2diffusion barrier showed that Ta is sufficiently bound to oxygen in the as-deposited state, butRuO2consists of Ru and Ru–O binding state. The Ta–O bonds showed little change compared to the as-deposited state with increasing annealing temperature, whereas Ru–O bonds significantly increased and transformed to conductive oxide,RuO2.Therefore, the Ta layer deposited byRuO2addition effectively prevented the indiffusion of oxygen up to 800 °C and its oxidation resistance was superior to various barriers reported by others.

ISSN:1071-1023    

DOI:10.1116/1.590342

出版商:American Vacuum Society    

年代:1998

数据来源: AIP

摘要:

We report the effects of flash “channel” programming, or severe gate disturb, on the threshold voltage of fast or overerased bits. Experiments have been performed to establish that this class of fast bits are nonerratic and remain fast after 250 °C bake. These fast bits exhibit identical subthreshold characteristics similar to that of a normal bit after ultraviolet erase, thus establishing that the initial charge stored on the floating gate is the same for both normal and fast bits. Polysilicon grain boundary enhanced electric fields which result in impact ionization by tunneling electrons, thus generating trapped positive charges in the grain boundary oxide ridges are believed to play an important role in the generation of fast bits.

ISSN:1071-1023    

DOI:10.1116/1.590343

出版商:American Vacuum Society    

年代:1998

数据来源: AIP

摘要:

A new field emission display (FED) panel structure with an auxiliary space was developed in order to increase the conductance of the system for evacuation and help evacuate the cavity inside the FED more effectively. Gas molecules in the main space of the panel can move easily into the auxiliary space through the multiple openings in the base plate and can then be pumped out through the exhaust tube at the auxiliary tank. For the very thin panel, in which the space between the face plate and base plate is 58μm,pressure drop characteristics during evacuation are very sensitive to the number of openings in the base plate. The main purpose of multiple openings in shortening evacuation time is to reduce pressure gradient inside the cavity. Additionally, the auxiliary space makes it easy to place various getters inside the FED panel and to maintain high vacuum for a prolonged lifetime of the FED.

ISSN:1071-1023    

DOI:10.1116/1.590344

出版商:American Vacuum Society    

年代:1998

数据来源: AIP

摘要:

Exposing active Spindt-type molybdenum field emission microcathode arrays toCH4resulted in increased electron emission. Exposures of 250 and 2500 L result in electron emission enhancement of106.2±41.0%and200.1±20.7%and a decrease in tip work function by10.2±5.6%and17.6±1.7%,respectively. The measured work function changes indicate the formation of molybdenum carbides on the field emitter tips.

ISSN:1071-1023    

DOI:10.1116/1.590444

出版商:American Vacuum Society    

年代:1998

数据来源: AIP

摘要:

We have investigated a simple yet powerful method for making sharp scanning tunneling microscopy tips of Pt/Ir. It consists of three electrochemical polish/etch steps, not requiring any special micropolishing. The tips, as seen by high-resolution transmission electron microscopy, are sharper than 20 Å. Furthermore, they are smooth, without mini tips and covered with an oxide layer not much thicker than the native one (as seen from a freshly cut wire) when all three steps are applied.

ISSN:1071-1023    

DOI:10.1116/1.590445

出版商:American Vacuum Society    

年代:1998

数据来源: AIP

摘要:

We evaluated the characteristics of single Si field emitters (Si-FEs) from the perspective of their use in electron guns. Since the current fluctuation of Si-FEs strongly depends on the product of vacuum pressurePand emission currentI, just as it does for conventional cold field emitters (CFEs), the mechanism of fluctuation was assumed to be similar to that of CFE. Such fluctuations are divided into two regions, the boundary was virtually equal to CFEs, at approximately3×10−12 Pa A.However, unlike as for CFEs, the emission current of Si-FEs drops abruptly after a certain duration. We found that the integral ofPIwith the duration time (PITintegral) is almost constant (approximately1×10−8 Pa A s) in various conditions and therefore assume that it correlates with the emission area of the emitter tip. The current leakage between emitter and gate electrode was found to be caused because of their small size. Responsible for this leakage are hydrocarbon contamination layers that were generated by emitted electrons or backscattered electrons on the surface of the insulating layer. Finally, we fabricated a miniaturized electron gun with Si-FEs and succeeded in obtaining SEM images with electrons that were emitted from the Si-FEs.

ISSN:1071-1023    

DOI:10.1116/1.590495

出版商:American Vacuum Society    

年代:1998

数据来源: AIP