摘要:

Emission microscopy has now become established as an effective technique in terms of reliability physics of industrial semiconductors. This convenient method allows chip verification and failure analysis to be carried out in many applications. Besides this, emission microscopy provides a technique for use in device engineering and the optimization of test structures. The key to using this technique to permit a more sophisticated quantitative analysis lies in a unique assignment of the light emission to the defect mechanism. Since the corresponding phenomena are numerous and their details are not fully clarified in all cases, further investigation is still required before this technique can be used routinely in a quantitative rather than qualitative approach. Some quantitative aspects of emission microscopy with respect to fundamental studies will therefore be outlined in this article, and the applicability of such practical guidelines will be illustrated. This provides the fundamentals for a comprehensive evaluation of the potential applications and degree of informativeness of this advanced method of failure analysis.

ISSN:0021-8979    

DOI:10.1063/1.350466

出版商:AIP    

年代:1992

数据来源: AIP

摘要:

Two types of signals are considered: infinite‐range signals and periodic signals. Tails of infinite‐range signals can be described with an asymptotic power series (having terms of the typex−nwithn≥2). For tails of periodic signals an asymptotic series [having terms of the type sin−n(&pgr;x/p) withp=period andn≥2] is derived from the asymptotic power series for the infinite‐range signals using Poisson summation. It is shown that for practical purposes the tails of a signal can be described quite satisfactorily with only a few terms of the series. On this basis nonmeasurable parts of tails of both symmetric and asymmetric signals can be estimated reliably and thus the effects of the unavoidable signal truncation can be counteracted.

ISSN:0021-8979    

DOI:10.1063/1.350545

出版商:AIP    

年代:1992

数据来源: AIP

摘要:

The stability of annealed proton exchange waveguides and devices in LiTaO3is examined by monitoring the output power ratio of passive directional couplers. This is shown to be an extremely sensitive technique for measuring waveguide stability. Mode propagation constants of planar waveguides and near‐field mode sizes and losses of channel waveguides are also measured as a function of time. Data from these measurements indicate that the refractive index profile is unstable and continuously evolves even for relatively long anneal times. The instabilities appear to lower the local change in the refractive index either through the room‐temperature migration of hydrogen or a change in the magnitude the refractive index increase due to the proton exchange. Assuming that the hydrogen concentration profile is stable, the decrease in the refractive index was estimated to be ≊10−3over a period of 90 days. Although the instabilities were seen in all of the fabricated devices, only a small portion of the total fabrication parameter space was investigated. Therefore, it is possible that the instability may be avoided as in LiNbO3, by using dilute melts or even longer anneal times.

ISSN:0021-8979    

DOI:10.1063/1.350546

出版商:AIP    

年代:1992

数据来源: AIP

摘要:

A set of coupled‐wave equations relative to degenerate four‐wave mixing is derived and solved for optically active Bi12(Ge;Si)O20cubic crystals. Nonlinear absorption is taken into account. Circular polarized waves are used. The calculated results concerning phase conjugation efficiency are compared to the experimental ones.

ISSN:0021-8979    

DOI:10.1063/1.350547

出版商:AIP    

年代:1992

数据来源: AIP

摘要:

Six TJS (transverse junction stripe) AlGaAs diode lasers were exposed to fast neutrons with fluences ranging from 2×1012to 3×1013n/cm2, and their tuning, gain, and dispersion curves were measured. The tuning and gain curves of four lasers showed blue shifts of several meV at neutron fluences as low as 2×1012n/cm2; the other two lasers never showed this blue shift. In addition, the lasers that displayed a blue shift also showed an increase in their threshold currents. None of the lasers exhibited any change in their dispersion curves. To explain the blue shift, it is hypothesized that neutron irradiation reduces the efficiency for lasing in the bandtail states of these devices, forcing lasing action to occur between states with greater energy separation. A model in which the reduced efficiency takes the form of a decrease in the transition matrix element is found to yield blue shifts of the correct order of magnitude. Though bandtail effects may also explain the difference in radiation sensitivity among the TJS lasers, at present the reason why only four of the six lasers blue shifted after neutron irradiation is not well understood.

ISSN:0021-8979    

DOI:10.1063/1.350548

出版商:AIP    

年代:1992

数据来源: AIP

摘要:

Interactions between optical beams incident upon and higher‐order self‐diffracted beam generated within an absorptive and optically active photorefractive crystal of 23 symmetry are investigated by solving a set of coupled differential equations. It is shown that, under favorable conditions, a significant amount of power may be transferred to the newly generated wave. Investigated are the effects of optical activity, thickness and absorption of the crystal, coupling constant, and off‐Bragg parameter on energy transfer to the higher‐order diffracted beam. Coupled wave equations are solved numerically by a fourth‐order Runge–Kutta method and results are presented in graphical form. The analysis is valid only for the near collinear interacting beams, i.e., in the limit of large grating spacing.

ISSN:0021-8979    

DOI:10.1063/1.350549

出版商:AIP    

年代:1992

数据来源: AIP

摘要:

The output beam power and small‐signal unsaturated gain on the He‐Cu 780.8 nm transition in a hollow slotted‐anode cathode laser are increased significantly by the application of a longitudinal magnetic field and each shows a marked dependence on the field in the range 10 to 40 mT. The laser output power and the gain increase with the discharge current, while the optimum magnetic field (∼22 mT) results in a further significant increase both in output power and gain. These effects have their origin in the transverse deflection of the beam electrons by the magnetic field.

ISSN:0021-8979    

DOI:10.1063/1.350550

出版商:AIP    

年代:1992

数据来源: AIP

摘要:

The longitudinal mode behavior of AlGaAs lasers withn‐type cladding layers doped with Se and Si is reported. The longitudinal mode of the lasers with highly Se‐doped cladding layer is stabilized, and large hysteresis of mode jump is observed as temperature changes. In the case of highly Si‐doped cladding layers, however, the mode hops to the adjacent one and no hysteresis is observed. These phenomena are explained by the difference in thermal activation energy between Se‐ and Si‐relatedDXcenters.

ISSN:0021-8979    

DOI:10.1063/1.350551

出版商:AIP    

年代:1992

数据来源: AIP

摘要:

To explore the laser kinetics of atomic xenon lasers pumped by an ultraviolet‐preionized, self‐sustained discharge, time‐resolved small‐signal gains are measured using a long‐pulse probe laser. Faster electron mixing processes among excited xenon manifolds in the 6pstate may affect the small‐signal gain distribution among 1.73, 2.03, and 2.65 &mgr;m laser lines, which share the same upper laser level Xe(5d[3/2]1) at excitation rates in excess of 160 kW/cm3. When the excitation rate in a late part of the discharge is increased, absorption caused by repumping of the lower laser level is observed at 1.73 &mgr;m. The measured gains are discussed in conjunction with multiline laser oscillation performance obtained by the same laser device.

ISSN:0021-8979    

DOI:10.1063/1.350552

出版商:AIP    

年代:1992

数据来源: AIP

摘要:

The thermal conductivity of thick‐film diamond prepared by chemical vapor deposition (CVD) has been measured with heat flowing in a direction perpendicular to the plane of the film. A laser flash technique with fast infrared detection has been devised for measurement of thin samples with high conductivity. The conductivity perpendicular to the plane is observed to be at least 50% greater than with heat flowing parallel to the plane. This anisotropy is attributed to low‐quality grain boundaries in the columnar microstructure. The observed dependence of the thermal conductivity on microstructure has important implications for thermal management of microelectronic devices with CVD diamond.

ISSN:0021-8979    

DOI:10.1063/1.350553

出版商:AIP    

年代:1992

数据来源: AIP