摘要:

Using two‐step annealing of wafers containing mechanically induced back‐surface damage, we have shown that the presence of stabilized damage regions controls the development of front‐surface defect denudation zones and internal SiOxnucleation. Using data from transmission electron microscopy, secondary ion mass specrometry profiling, and secondary ion microscopy measurements we have demonstrated that little or no direct correlation exists between measured (front‐surface) oxygen depletion widths and defect denudation zone widths. Primary anneals at temperatures <600 °C have also been shown to producenosignificant or measurable depletion of oxygen at the front surface of wafers.

ISSN:0003-6951    

DOI:10.1063/1.92829

出版商:AIP    

年代:1981

数据来源: AIP

摘要:

Ann‐GaAs/p‐GaSb heterojunction intercell Ohmic contact (IOC) has been formed by a laser bonding procedure. Resistance per unit area of 5×10−3&OHgr;‐cm2has been obtained as an upper limit. This IOC is able to provide sufficiently good electrical connection between two adjacent subcells of a monolithic multicolor solar converter operating at several hundred suns concentration with the insignificantI2Rloss.

ISSN:0003-6951    

DOI:10.1063/1.92836

出版商:AIP    

年代:1981

数据来源: AIP

摘要:

The electron multiplication factors of electron bombardment induced conductivity (EBIC) of 300–500 were obtained with a hydrogenated amorphous silicon (a‐Si:H) film of higher resistivity than 1010&OHgr; cm at an accelerating voltage of 7 kV. The response time of the EBIC current for a pulsed primary electron beam was determined to be shorter than 1 ms for both build‐up and decay lags. It is found that an EBIC target of ana‐Si:H film has promising properties for application to imaging devices at low light levels.

ISSN:0003-6951    

DOI:10.1063/1.92837

出版商:AIP    

年代:1981

数据来源: AIP

摘要:

Highly conductive films of zinc oxide have been prepared by reactive rf magnetron sputtering from an oxide target. Film conductivities ranging from ∼10−8&OHgr;−1 cm−1to 5×102&OHgr;−1 cm−1can be obtained depending on the sputter conditions. Films with sheet resistivities of 85 &OHgr;/&laplac; showed little absorption and ∼90% transmission between &lgr; = 4000→8000 A˚. A second low power discharge at the substrate is used to initiate growth of the highly conducting material on room‐temperature substrates. Thus, during the deposition of insultating ZnO, turning on this second discharge causes the deposition to ’’switch’’ from low conductivity to high conductivity material. This is of particular interest in the fabrication of semiconductor‐insulator‐semiconductor solar cells where precise control over the thickness of the insulating layer is necessary and where a highly transparent and conductive window‐junction layer is required.

ISSN:0003-6951    

DOI:10.1063/1.92815

出版商:AIP    

年代:1981

数据来源: AIP

摘要:

Colorless, transparent, purec‐oriented AlN films have been deposited on glass substrates, with and without Cr‐Au films, utilizing a modified sputter gun. The design of the gun and of the sputtering system helps to keep the growing surface free from charged particle bombardment and excessive heat by radiation. Attention will be focused mainly on the effect of total sputtering pressure on the quality of the AlN films. A very strong magnetic field makes it possible to sputter at pressures as low as 0.133 Pa (1 &mgr;Torr). This high vacuum sputtering improvesc‐orientation, surface smoothness, film color, transparency, deposition rate, and thermal expansion coefficient matching. The deposition rate of the sputter gun is as high as 2.4 &mgr;m/h at input power of 300 W.

ISSN:0003-6951    

DOI:10.1063/1.92838

出版商:AIP    

年代:1981

数据来源: AIP

摘要:

Reduced pressure, chemical vapor deposited polycrystalline silicon films (5000 A˚ thick) over thermally grown SiO2on (100) silicon wafers are recrystallized by a scanning electron microscope modified electron beam annealing system. On the basis of transmission electron microscope bright‐field images and electron diffraction patterns, large grained polycrystalline silicon films of 20‐&mgr;m average grain size are obtained after electron beam annealing. Electron beam current, scanning rate, and annealing repetition are found to be important parameters in the recrystallization. Optimum values for them are from 1.6 to 1.9 mA, from 40 to 80 cm/sec, and from 5 to 10 times, respectively.

ISSN:0003-6951    

DOI:10.1063/1.92839

出版商:AIP    

年代:1981

数据来源: AIP

摘要:

Interactions between two independently biased thin‐film superconducting microbridges yield a voltage step in the current‐voltage characteristics of the bridges. Perturbation theory applied to the quasiparticle coupling currents explains these results as apparent critical current depression due to a regenerative feedback effect. Calculated changes in the critical current caused by the combined effects of order parameter depression, dc and ac quasiparticle coupling currents are in good agreement with experiments.

ISSN:0003-6951    

DOI:10.1063/1.92840

出版商:AIP    

年代:1981

数据来源: AIP

摘要:

We have studied the parametric amplification properties of an internally pumped Josephson tunnel junction, where the shunt contained resistive and inductive components. The amplification was, in this case, limited by circuit component values to less than 8 dB at 10 GHz, but it was very stable against variations in bias conditions. The amplifier gain‐bandwidth product was large and the noise level very low. We estimated the noise temperature to be less than 50 K, which should make the device attractive for mm‐wave amplification.

ISSN:0003-6951    

DOI:10.1063/1.92841

出版商:AIP    

年代:1981

数据来源: AIP

摘要:

A novel Josephson logic gate achieving high gain, employing current injection, and having a noninterferometer configuration has been proposed and studied. The gate includes three small junctions for input sensing, output driving, and I‐O isolation. The junctions are appropriately biased by source resistors to obtain high current gain. Computer simulation and preliminary experiment have demonstrated that a current gain higher than 2 can easily be obtained through the proposed configuration.

ISSN:0003-6951    

DOI:10.1063/1.92808

出版商:AIP    

年代:1981

数据来源: AIP

摘要:

We have measured the properties of a superconductor‐insulator‐superconductor quasiparticle mixer which is operated in the quantum limit. Single sideband conversion gain larger than +4 dB was observed at 36 GHz with a mixer noise temperatureT= 9±6 K, which is to be compared with the (Planck) quantum limit h&slash;&ohgr;/(k ln 2)≃2.5 K. Complete three‐port mixer calculations are presented which are in good agreement with the gain measurements. The dynamic resistance was observed to become infinite and then negative as the source conductance was decreased. This implies that arbitrarily large gain is available. The negative resistance is accompanied by IF oscillations.

ISSN:0003-6951    

DOI:10.1063/1.92809

出版商:AIP    

年代:1981

数据来源: AIP