摘要:

High aspect-ratio gated field emitter arrays have been fabricated using silicon tip prepared by the anodization of a silicon wafer with periodicn/pjunctions. The tips were formed by the preferential growth of porous silicon inp-type material and were transferred to a separate silicon substrate by direct bonding. Gate electrodes were then formed by depositing a WSi2film over the tips, and apertures were subsequently created by etching with an argon milling process. The resulting gated tip arrays demonstrated field emission, although higher than usual gate voltages were required.

ISSN:1071-1023    

DOI:10.1116/1.589875

出版商:American Vacuum Society    

年代:1998

数据来源: AIP

摘要:

An experimental and theoretical analysis of integrated nanotips and field emission arrays is presented in this article. Atomic force and scanning electron microscopy techniques were used to characterize the morphology of the monotips apex. Different positions of the tip with respect to the extraction lenses and morphologies were observed leading to different values of the tip emission current. Numerical calculations were performed considering the integrated tip as an electrostatic two-dimensional system allowing study of potential distributions, electrostatic fields near the tip apex, current density of emitted electrons, and electron trajectories. The correlation between experimental and theoretical results allows us to better understand the effect that the geometrical properties of the integrated nanotips, such as misalignments or morphology failures, produce on the emission current. Experiments and theory support the idea that the best emission is obtained for centered sharper tips with their apex localized at the level of the extraction lenses. Furthermore, slight modifications of the tip geometry lead to significant changes in the current distribution of emitted electrons.

ISSN:1071-1023    

DOI:10.1116/1.589876

出版商:American Vacuum Society    

年代:1998

数据来源: AIP

摘要:

A vacuum microdiode with a moving anode was fabricated by means of a new process requiring only two mask levels and only one critical etching step. The cathode, with a pyramidal shape, was made by anisotropically etchingpsilicon through a mask formed by the anode itself, which, at the end of the process, consists of aSiO2suspended membrane supporting an Al layer. The process is compatible with standard complementary metal-oxide-semiconductor technology.I–Vcharacteristics were measured under vacuum verifying also that the diode current is sensitive to visible light irradiation and to changes of the anode-to-cathode distance. A minimum anode-cathode distance of about 5000 Å was obtained.

ISSN:1071-1023    

DOI:10.1116/1.589877

出版商:American Vacuum Society    

年代:1998

数据来源: AIP

摘要:

The effect of gas species on the degradation of gate oxides due to plasma exposure in reactive ion etching has been investigated. Gases tested wereH2, Ar, Xe, andO2. The oxide degradation was evaluated by applying a constant-current stress and measuring the charge-to-breakdownQbdof metal/oxide/silicon capacitors. It has been found thatO2plasma significantly degrades the reliability of the gate oxide. Characterization of plasmas using a Langmuir probe has shown thatO2gas tends to produce nonuniform plasma because of its electronegative nature, and thus enhances degradation of gate oxide.

ISSN:1071-1023    

DOI:10.1116/1.589878

出版商:American Vacuum Society    

年代:1998

数据来源: AIP

摘要:

Ion-beam milling was used for sharpening of diamond particles on ends of silicon tips. The sharpened diamond samples were used as field-electron emitters.I–Vcharacteristics of the emitters were measured. An effect of conditioning of the emitters was observed: After an emitter worked at least several hours, its current increased for several orders of magnitude and became stabilized.

ISSN:1071-1023    

DOI:10.1116/1.589879

出版商:American Vacuum Society    

年代:1998

数据来源: AIP

摘要:

Thin-film cold cathodes have been grown on molybdenum by a modified microwave assisted plasma chemical vapor deposition diamond process. Electron field-emission tests have been performed on the devices. The modification from the chemical vapor deposition diamond process includes the addition ofN2andO2into the plasma during the growth stage. Characterization of these films indicates a disordered tetrahedral carbon structure. Raman spectroscopy shows a disturbance in the cubic symmetry of the lattice and x-ray diffraction indicates a disordered tetrahedral structure. Electron emission testing indicate low turn-on voltages. Current densities from 1 to8 mA/cm2can be obtained for applied fields of 5–8 V/μm. The results are explained in terms of a change in the electronic band structure and the formation of states in the band gap.

ISSN:1071-1023    

DOI:10.1116/1.589880

出版商:American Vacuum Society    

年代:1998

数据来源: AIP

摘要:

Electron field emission characteristics of uniformly constructed micro-pyramids of polycrystalline diamond with varyingsp2content have been systemically investigated. Concurrently, tip surface treatment was performed and emission characteristics of the post-treated tips were evaluated. The experimental results show that the field emission characteristics of the diamond can be enhanced by increasing thesp2content and performing surface treatment. The emission current is significantly improved and the turn-on electric field is drastically reduced. Hypotheses are proposed for the effect ofsp2content and surface treatment on the field emission enhancement of diamond tips: (i) lowering of the work function due tosp2defect induced band and impurity desorption, and (ii) increase in field enhancement factor due tosp2-diamond-sp2microstructures and a field forming process. Analysis of the experimental results indicates that (ii) is the more probable explanation.

ISSN:1071-1023    

DOI:10.1116/1.589881

出版商:American Vacuum Society    

年代:1998

数据来源: AIP

摘要:

Field emission from diamond and cubic boron nitride coated emitters has been investigated by field emission energy distribution (FEED) analysis. In order to study the mechanisms governing the emission process, we developed a modified FEED technique that consisted of measuring electron energy spectra as a function of the extraction voltage applied to the field emitter. This technique has led to a detailed study of band bending effects due to field penetration. Voltage drop across the emitting, wide-band-gap layers (thickness typ. 0.5μm) was in the order of 1% of the applied extraction voltage. The observed FEED spectra and their dependence on the extraction voltage were explained in terms of a simplified band model. In nominally undoped diamond and cubic boron nitride samples, field emission was found to originate from the conduction band minimum. Injection of electrons from the metallic back contact into the wide-band-gap material has been identified as the essential limiting factor to the emission current.Mo2C interlayers between Mo back contacts and emitting diamond layers were formed by annealing at 500 °C for several hours and led to more stable emission currents, typically enhanced by more than one order of magnitude.

ISSN:1071-1023    

DOI:10.1116/1.589882

出版商:American Vacuum Society    

年代:1998

数据来源: AIP

摘要:

A systematic investigation of deposition parameters and post-treatments was performed for the development of field emission displays based on flat chemical vapor deposited diamond films. The lowest onset field strengths were obtained for films grown at the highest substrate temperature, highest methane content, and with negatively biased substrate. Intentionally damaging the films by implantation with 50 keV and 100 keV carbon ions as well as with 4.4 MeV silicon ions usually resulted in an enhanced field emission. The emission followed the Fowler–Nordheim law up to 0.5 mA/mm2, and a current carrying ability of more than 100 mA/mm2was detected. Considerably improved emission was achieved by short and long-term processing at higher current levels.

ISSN:1071-1023    

DOI:10.1116/1.589883

出版商:American Vacuum Society    

年代:1998

数据来源: AIP

摘要:

Experiments have been carried out to study the field electron emission characteristics of nitrogen-doped amorphous diamond thin films prepared by magnetic-field filtered carbon ion deposition. A transparent anode imaging technique is used to record the spatial distribution of individual emission sites and the total emission current–voltage characteristics of the films. Also, the optical and electrical properties of the films having different nitrogen-doping levels have been studied. A correlation has been found to exist between the field-emission characteristics and the band gap of the films; i.e., it is found that the films of relatively small optical band gap have low turn-on fields.

ISSN:1071-1023    

DOI:10.1116/1.589884

出版商:American Vacuum Society    

年代:1998

数据来源: AIP