摘要:

The dielectric breakdown mechanism in thin gate oxides is discussed based on the temperature dependence of hole fluence to dielectric breakdown through gate oxides. It has been demonstrated for the first time that the hole fluence to dielectric breakdown is not a constant value for different oxide fields but has a strong oxide field dependence at low temperatures. It has been also found that the dominant dielectric breakdown mechanism changes at around 150 K. At higher temperatures than 150 K, the dielectric breakdown mechanism in silicon‐dioxide is not dependent on the oxide field. On the other hand, the dielectric breakdown at lower than 150 K is dominated by the mechanism strongly dependent on the oxide field. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.113782

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

This work characterizes a GaN:Mg on silicon ultraviolet photodetector with a cutoff at 3.3 eV and a responsivity of 12 A/W at 4 V bias for optical intensities on the order of 1 W/m2and below. A weak photovoltaic response is also reported. The photocurrent is nearly linear versus optical intensity for up to 10 W/m2. The responsivity increases nearly linearly with applied voltage up to 8 V, then the increase slows toward saturation. To explain this high responsivity in a direct gap semiconductor, it is hypothesized that holes are captured at either compensated Mg deep acceptor sites or Mg‐related trap/recombination centers, resulting in a greatly prolonged electron free‐carrier lifetime. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.113783

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

A novel microshadow mask technique forinsitupatterning of multilayers is presented. It is ideally suited to fabricate YBa2Cu3Ox(YBCO) and insulator lines with gently sloping edges, needed for high quality insulated superconducting crossovers. The critical current densityjc(T=77 K) of a YBCO/SrTiO3/YBCO crossover exceeds 2×106A/cm2in both the bottom and the top YBCO stripline. The insulating SrTiO3layer of 200 nm thickness displays a high resistivity of &rgr;≳108&OHgr; cm (T=77 K). The extremely smooth morphology of the edges has been revealed by cross sectional transmission electron microscopy, indicating a stepflow mechanism of YBCO growth. Multiturn flux transformers with a 15 &mgr;m linewidth input coil spiral have been fabricated by this microshadow mask technique. A transformer with a pickup loop area of 7 mm2has been coupled to a 1 mm2washer dc SQUID in flip chip geometry. In comparison to the bare SQUID a magnetic flux gain factor of 9 has been obtained. The white noise level of this setup was determined to be 8×10−5&Fgr;0/Hz1/2at 77 K. It was entirely due to the intrinsic noise of the employed dc SQUID itself. The 1/fnoise level increased a factor of 2. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.113784

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

Photoemission oscillations are observed from (001) GaAs, AlAs, AlGaAs, InAs, and AlSb. The periodicity of the oscillations corresponds to that of reflection high‐energy electron diffraction oscillations measured using the same growth conditions. For both methods, the oscillation amplitude is strongly dependent on the substrate temperature, III/V flux ratio, and the nature of the surface on which growth is nucleated for the oscillation measurement. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.113785

出版商:AIP    

年代:1995

数据来源: AIP

ISSN:0003-6951    

DOI:10.1063/1.114228

出版商:AIP    

年代:1995

数据来源: AIP