摘要:

The desorption of fluorine from barium fluoride thin films deposited on silicon substrate has been observed due to the incidence of electron beam during Auger electron spectroscopic (AES) studies. Slow electron energy loss spectroscopy (SEELS) has been employed to observe changes in core levels and color center formation. The desorption cross section for fluorine and the critical electron beam dose necessary to initiate electron‐stimulated desorption have been estimated. The results are envisaged to provide information to investigators performing AES on such materials to choose parameters so as to eliminate or reduce beam damages. Since the desorption of fluorine results in metalliclike barium on the surface, it can also be a technique to deposit clean Ba layers on cathode materials to achieve work‐function reduction.

ISSN:0021-8979    

DOI:10.1063/1.346511

出版商:AIP    

年代:1990

数据来源: AIP

摘要:

We have fabricated a Si metal‐oxide‐semiconductor field‐effect transistor with a 20‐nm channel length using a novel step/edge technique. An Al gate is evaporated onto a step in the SiO2gate oxide. A second Al gate, separated from the first by a plasma‐enhanced chemical‐vapor‐deposited SiO2layer, provides inversion layer extensions of the source and drain contacts. Electrical conductance measurements indicate a channel length approximately equal to the fabricated gate length.

ISSN:0021-8979    

DOI:10.1063/1.346512

出版商:AIP    

年代:1990

数据来源: AIP

摘要:

The hysteresis (extrinsic) and current‐voltage (I‐V) characteristics of the multiwell, vertically integrated, resonant‐tunneling diode are analyzed. Our analysis shows that hysteresis in the vertically integrated diode I‐V can result from interchanging the order in which the devices switch, depending if the bias is increasing or decreasing. Experimental results are presented that support this analysis.

ISSN:0021-8979    

DOI:10.1063/1.346513

出版商:AIP    

年代:1990

数据来源: AIP

摘要:

The relaxation oscillation frequency ofp‐substrate buried crescent InGaAsP lasers is measured as a function of the output power in the switched‐on state. The lasers are excited by a steplike current pulse at room temperature. The highest resonance frequency observed for a 350‐&mgr;m long cavity is 12.1 GHz equivalent to an intrinsic 3‐dB cutoff frequency of 18.8 GHz at an optical power of 9 mW/facet according to an injection current of 3.8 times threshold current, this is so far the best ever published value for ap‐substrate laser.

ISSN:0021-8979    

DOI:10.1063/1.346514

出版商:AIP    

年代:1990

数据来源: AIP

摘要:

Electroluminescence from the drain‐edge of GaAs/AlGaAs heterostructure metal‐semiconductor field‐effect transistors under high applied drain bias is observed. The visible light emission is seen through Monte Carlo simulations to be correlated with Gunn domains in the sample, in which the high‐field region gives rise to both impact ionization current and the luminescent emission.

ISSN:0021-8979    

DOI:10.1063/1.346515

出版商:AIP    

年代:1990

数据来源: AIP

摘要:

We use infrared absorption spectroscopy to study both the electronic excitation and the local vibrational mode (LVM) of the carbon acceptor in semi‐insulating GaAs as a function of EL2 photoquenching. The behavior of the far‐infrared electronic lines shows that the normally compensated carbon becomes neutralized (i.e., changes its charge state from singly negative to neutral) when the EL2 absorption is photoquenched. At the same time, the LVM absorption band shows no change in spectral form or vibrational frequency of its fine structure after photoquenching which indicates that, contrary to expectations, a charge‐state change has no measurable effect on this band.

ISSN:0021-8979    

DOI:10.1063/1.346516

出版商:AIP    

年代:1990

数据来源: AIP

摘要:

We report on a modified optically detected magnetic resonance (ODMR) technique, here called delayed ODMR (D‐ODMR), for studies of geometric (atomic) and electronic structure of defects in semiconductors. This D‐ODMR technique is shown to be very successful in overcoming the dominating optically detected cyclotron resonance background signal in ODMR studies of defects in Si and GaAs.

ISSN:0021-8979    

DOI:10.1063/1.346517

出版商:AIP    

年代:1990

数据来源: AIP

摘要:

The direct synthesis of silicon oxinitride films by multipulse excimer (&lgr;=308 nm) laser irradiation in a nitrogen‐containing ambient gas is reported featuring characteristics consistent with potential application in microelectronics.

ISSN:0021-8979    

DOI:10.1063/1.346518

出版商:AIP    

年代:1990

数据来源: AIP

摘要:

The ablation and patterning of Y–Ba–Cu–O films on (100) SrTiO3and (100) MgO substrates by KrF excimer‐laser light projection was investigated. Three different regimes of laser‐material interactions were observed. Transition temperatures and critical current densities in laser‐fabricated strip lines were investigated.

ISSN:0021-8979    

DOI:10.1063/1.346519

出版商:AIP    

年代:1990

数据来源: AIP

摘要:

The surface resistanceRsof YBa2Cu3O7(YBCO) thin films (0.6±0.1 &mgr;m) deposited onto 2.5‐cm diam (100) LaAlO3substrates has been measured at 22 GHz using both Cu and Nb cavities. The surface resistance falls precipitously at the superconducting transition (Tc=90 K) from a normal state value of approximately 2 &OHgr; to a 77 K value of 13.7±1 m&OHgr;, which is 1.6 times lower than Cu. At 4 K the surface resistance is 1±0.1 m&OHgr;, as measured in a Nb superconducting cavity, which is an order of magnitude lower than Cu. The critical current density at 77 K is 4.5×104A/cm2. Pole figure analyses show the ratio ofc‐axis toa‐axis‐oriented material in the film is 2.4:1. YBCO films deposited onto either LaGaO3or LaAlO3substrates with varyingc/aratios yield surface resistance values at 77 K that are crudely correlated withRs. Therefore, the principal effect of orienting the material is to improve the sharpness of the high‐frequency superconducting transition, consistent with the notion that the sharpness is associated withintergranularrather thanintragranularproperties.

ISSN:0021-8979    

DOI:10.1063/1.346493

出版商:AIP    

年代:1990

数据来源: AIP