摘要:

The recombination lifetime &tgr;rhas been measured at low temperature in Sip‐channel metal oxide semiconductor field effect transistors (MOSFET’s) using the charge pumping technique. Measurements were performed over the 40–300‐K range. A monotonically increasing lifetime with decreasing temperature was measured. &tgr;rwas found to be proportional to exp(Ar/kT), whereAris a constant determined from the slope of ln &tgr; vs 1/T. For a typical MOSFET the lifetime ranged from 80 ns at 300 K to 370 &mgr;s at 100 K. The value ofArin this case was determined to be 106 meV.

ISSN:0003-6951    

DOI:10.1063/1.92644

出版商:AIP    

年代:1981

数据来源: AIP

摘要:

Boron implantation into diamond at room temperature leads to significant irreversible volume expansion when the boron dose exceeds 5×1015cm−2. This observation is presumed to reflect an upper limit in the extent to which diamond can be effectively doped with boron by ion implantation. Similar limitations associated with other implant species are anticipated.

ISSN:0003-6951    

DOI:10.1063/1.92645

出版商:AIP    

年代:1981

数据来源: AIP

摘要:

Deep‐level transient spectroscopy experiments, performed on31P+‐implanted and laser‐annealed silicon, have shown that the defect concentration is considerably reduced when a conventional thermal annealing is performed before the laser treatment. A model is presented which explains the origin of the defects.

ISSN:0003-6951    

DOI:10.1063/1.92646

出版商:AIP    

年代:1981

数据来源: AIP

摘要:

A laser‐activated avalanche transistor compatible with planar processing has been devised. TheI‐Vcharacteristics display current‐controlled negative differential resistance similar to a bidirectional triggering diode. Capability as an edge detector or as a comb generator was demonstrated. An avalanche current gain of 24 carriers/photon with a 20‐V bias was observed when the transistor was used as an optical pulse detector.

ISSN:0003-6951    

DOI:10.1063/1.92647

出版商:AIP    

年代:1981

数据来源: AIP

摘要:

A novel three‐step process for producing low‐defect‐density epitaxial silicon layers on sapphire substrates has been developed. The three‐step process utilizes a simple room‐temperature ion implantation and solid‐phase epitaxial regrowth. Both megaelectron volt helium backscattering and transmission electron microscopy (TEM) results indicate the excellent crystalline quality of silicon‐on‐sapphire (SOS) wafers produced by the three‐step process. The backscattering minimum yields at the interface and the surface of the three‐step SOS layer are 0.14 and 0.03, respectively. A TEM micrograph of the top 500 A˚ of the three‐step SOS layer shows none of the planar defects which are common to standard SOS layers.

ISSN:0003-6951    

DOI:10.1063/1.92648

出版商:AIP    

年代:1981

数据来源: AIP

摘要:

Electromigration was investigated in 1×4×250 &mgr;m aluminum conductors which were recrystallized to produce chains of single‐crystal grains, ’’bamboo’’ structures. Median lifetimes were substantially longer than are found in normal polycrystalline Al, reflecting the lack of grain boundary diffusion paths. However, mass fluxes estimated from damage features were larger and more variable than is consistent with a normal lattice diffusion mechanism. An enhanced lattice diffusion mechanism is proposed to account for these observations.

ISSN:0003-6951    

DOI:10.1063/1.92649

出版商:AIP    

年代:1981

数据来源: AIP

摘要:

An InP avalanche photodiode with a guard ring structure is fabricated. The maximum avalanche gain obtained is 210 at a primary photocurrent of 0.2 &mgr;A, and uniform photoresponse without local enlargement is obtained at an avalanche gain of 10. Multiplication noise characteristics are investigated, and the effective ionization rate ratio of holes to electrons is found to be 1.7–1.8.

ISSN:0003-6951    

DOI:10.1063/1.92650

出版商:AIP    

年代:1981

数据来源: AIP

摘要:

A tunable resonator in the gigahertz‐range using circular sine‐Gordon fluxons or pulsons on a lossy large‐area Josephson junction with a circular impurity in the Josephson current density is proposed. To obtain steady tunable oscillations in a lossy medium, one must supply energy (’’negative’’ resistance). We propose to control the constant bias current with an autonomous pulson velocity‐sensitive switch. One possibility for fine tuning the oscillations is to vary the strength of the Josephson impurity current.

ISSN:0003-6951    

DOI:10.1063/1.92651

出版商:AIP    

年代:1981

数据来源: AIP

摘要:

The acoustic emission and voltage measurements were used to identify quench sources in a current‐carrying superconductor. The sources identified were (i) conductor motion, (ii) epoxy cracking, and (iii) pure joule heating resulting from the conductor reaching critical current. The combination of these two techniques appears to be a promising diagnostic tool in probing premature quenches in superconductors and superconducting magnets.

ISSN:0003-6951    

DOI:10.1063/1.92652

出版商:AIP    

年代:1981

数据来源: AIP

摘要:

Irradiation by neutrons and ions in A15 superconductors (Nb3Sn, V3Ga) exerts a stronger influence on the pinning behavior than in nonordered alloys (NbTi). In this work it is shown for deuteron irradiated Nb3/Sn wires prepared by the bronze process that the dose curve of the volume pinning forcePVcan be conveniently described by a sum of two terms, due to the grain boundary pinning and to the radiation pinning, respectively. After deduction of the contribution by the radiation‐induced pinning centers, good agreement is obtained between the measuredPVvalues and those calculated using the upper critical fieldBc2and the transition temperatureTcon the basis of the irradiation fluence. The use of a theoretical relationship betweenBc2andTcis supported by measured values. Application to multifilamentary superconductors with high current carrying capabilities simplifies the calculation ofPV, since the radiation induced volume pinning force can be neglected.

ISSN:0003-6951    

DOI:10.1063/1.92653

出版商:AIP    

年代:1981

数据来源: AIP