摘要:

In this letter, we report on the impact of the suppression of boron diffusion via nitridation of SiO2on gate oxide integrity and device reliability. SiO2subjected to rapid thermal nitridation in pure nitric oxide (NO) is used to fabricate thin oxynitride gate dielectrics. Bothn+polycrystalline silicon (polysilicon) gatedn‐MOS (metal–oxide semiconductor) andp+‐polysilicon gatedp‐MOS devices were subjected to anneals of different times to study the effect of dopant diffusion on gate oxide integrity. As expected, an advanced oxynitride gate dielectric will effectively alleviate the boron‐penetration‐induced flatband voltage instability inp+‐polysilicon gatedp‐MOS capacitors due to the superior diffusion barrier properties. However, such improvements are observed in conjunction with some degradation of the oxide reliability due to the boron‐blocking/accumulation inside the gate dielectric. Results show that even though the oxide quality is slightly degraded for NO‐nitrided SiO2withp+‐polysilicon gates,p‐MOSFETs (metal–oxide semiconductor field effect transistors) with these dielectrics still show improved interface stability as compared to conventional SiO2due to the reduced boron penetration into the Si/SiO2interface and underlying channel region. ©1996 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.115595

出版商:AIP    

年代:1996

数据来源: AIP

摘要:

Excitonic photoluminescence in a transverse electric field has been studied in strained Si1−xGex/Si type‐I quantum wells (QWs) in the weak field regime. With increasing electric field, a steady blue‐shift of the free exciton emission energies has been observed, thereby suppressing the anticipated downward shift due to a quantum confined Stark effect. It is revealed that a field‐driven decrease of the exciton binding energies gives a good account of the experimental blue‐shift for a wide range of well widths, which is also in good agreement with variational calculations. We also find that the extremely small conduction band offset characteristic of stained Si1−xGex/Si type‐I QWs is responsible for the absence of the Stark red‐shift and the mixed dimensionality. ©1996 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.115596

出版商:AIP    

年代:1996

数据来源: AIP

摘要:

AlxGa1−xN (0≤x≤0.50) ultraviolet photoconductors with a minimum cutoff wavelength shorter than 260 nm have been fabricated and characterized. The AlGaN active layers were grown on (00⋅1) sapphire substrates by metalorganic chemical vapor deposition (MOCVD). The spectral responsivity of the GaN detector at 360 nm is about 1 A/W biased at 8 V at room temperature. The carrier lifetime derived from the voltage‐dependent responsivity is 0.13–0.36 ms. ©1996 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.115597

出版商:AIP    

年代:1996

数据来源: AIP

摘要:

Exposure to a hydrogen plasma at 250 °C ofp‐type GaN (Ca) prepared by either Ca+or Ca+plus P+co‐implantation leads to a reduction in sheet carrier density of approximately an order of magnitude (1.6×1012cm−2to 1.8×1011cm−2), and an accompanying increase in hole mobility (6 cm2/V s to 18 cm2/V s). The passivation process can be reversed by posthydrogenation annealing at 400–500 °C under a N2ambient. This reactivation of the acceptors is characteristic of the formation of neutral (Ca–H) complexes in the GaN. The thermal stability of the passivation is similar to that of Mg–H complexes in material prepared in the same manner (implantation) with similar initial doping levels. Hydrogen passivation of acceptor dopants in GaN appears to be a ubiquitous phenomenon, as it is in otherp‐type semiconductors. ©1996 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.115598

出版商:AIP    

年代:1996

数据来源: AIP

摘要:

InGaN multi‐quantum‐well (MQW) structure laser diodes fabricated from III‐V nitride materials were grown by metalorganic chemical vapor deposition on (111) MgAl2O4substrates. The mirror facet for a laser cavity was formed by polishing III‐V nitride films grown on (111) MgAl2O4substrates. As an active layer, the InGaN MQW structure was used. The laser threshold current density was 8 kA/cm2. At a current above laser threshold, stimulated emission was observed with a sharp peak of light output at 410 nm that had a full width at half‐maximum of 2.1 nm under pulsed current injection at room temperature. ©1996 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.115599

出版商:AIP    

年代:1996

数据来源: AIP

摘要:

We report the realization of a bright and stable electroluminescent Schottky diode based on aluminum‐porous silicon junction. White light, visible in normal daylight, is emitted when a reverse bias is applied to the device, promoting the junction breakdown. The device has a fast (100 ns) rise time of the light emission. An excellent stability, tested over more than one month of continuous operation at a high bias level, is achieved by the complete encapsulation of the active porous silicon under a transparent alumina layer. The external power efficiency of light emission is 0.01%. ©1996 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.115600

出版商:AIP    

年代:1996

数据来源: AIP

摘要:

High structural and optical quality InxGa1−xP/GaAs quantum wells, withxfrom 0.51 to 0.45, have been successfully grown by atomic layer molecular beam epitaxy. In that compositional range, an important blue shift of the quantum well luminescence lines is observed, which is explained by an increase of the conduction band gap offset from compressive to tensile strain conditions. The luminescence intensity decreases with temperature above 20–30 K, which is attributed to impurities located at the interfaces and inside the quantum wells. The influence of the In content on the oscillator strength of the optical transitions is also evaluated. ©1996 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.115601

出版商:AIP    

年代:1996

数据来源: AIP

摘要:

A voltage‐controlled tunable two‐color infrared detector with photovoltaic (PV) and photoconductive (PC) dual‐mode operation at 3–5 &mgr;m and 8–14 &mgr;m using GaAs/AlAs/AlGaAs double barrier quantum wells (DBQWs) and bound‐to‐continuum GaAs/AlGaAs quantum wells is demonstrated. The photoresponse peak of the photovoltaic GaAs/AlAs/GaAlAs DBQWs is at 5.3 &mgr;m, and that of the photoconductive GaAs/GaAlAs quantum wells is at 9.0 &mgr;m. When the two‐color detector is under a zero bias, the spectral response at 5.3 &mgr;m is close to saturate and the peak detectivity at 80 K can reach 1.0×1011cmHz1/2/W, while the spectral photoresponsivity at 9.0 &mgr;m is absolutely zero completely. When the external voltage of the two‐color detector is changed to 2.0 V, the spectral photoresponsivity at 5.3 &mgr;m becomes zero while the spectral photoresponsivity at 9.0 &mgr;m increases comparable to that at 5.3 &mgr;m under zero bias, and the peak detectivity (9.0 &mgr;m) at 80 K can reach 1.5×1010cmHz1/2/W. Strictly speaking, this is a real bias‐controlled tunable two‐color infrared photodetector. We have proposed a model based on the PV and PC dual‐mode operation of stacked two‐color QWIPs and the effects of tunneling resonance with narrow energy width of photoexcited electrons in DBQWs, which can explain qualitatively the voltage‐controlled tunable behavior of the photoresponse of the two‐color infrared photodetector. ©1996 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.115602

出版商:AIP    

年代:1996

数据来源: AIP

摘要:

Trivalent siliconPb0andPb1defects were identified at both the top Si(100)/buried‐SiO2and buried‐SiO2/bottom‐Si(100) interfaces in high‐temperature (1320 °C) annealed Si/SiO2/Si struc‐ tures. The paramagnetic defects are generated by annealing in a flow of pure nitrogen (N2) or forming gas [N2H2; 95:5 (by volume)] at 550 °C. In addition, the forming‐gas anneal also generated positive charge in the buried oxides; significant lateral nonuniformities in the buried oxide charge density were observed following this anneal. These macroscopic inhomogeneities may be linked to previous reports of homogeneity related problems involving the SIMOX buried oxide, such as early breakdown and etch pits, suggesting that these types of measurements may be useful as nondestructive screens of SIMOX wafer quality. ©1996 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.115603

出版商:AIP    

年代:1996

数据来源: AIP

摘要:

Transmission zero engineering in lateral double‐barrier resonant tunneling devices is investigated. We show that, by inserting a resonant cavity in the quantum well region of a lateral double‐barrier resonant tunneling structure and engineering the placement of transmission zero‐pole pairs, the current peak‐to‐valley ratio of the device can be drastically improved at low temperature. An advantage of this structure also is that a lower peak voltage can be obtained compared to the corresponding lateral double‐barrier resonant tunneling device. ©1996 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.115604

出版商:AIP    

年代:1996

数据来源: AIP