摘要:

SrTiO3thin films were deposited by low‐pressure organometallic chemical vapor deposition. Titanium isopropoxide, Sr(dipivaloylmethanate)2, oxygen, and water vapor were used as reactants, and argon was used as a carrier gas. Growth rates ranging from 0.3 to 4.5 &mgr;m/h were obtained on (0001) sapphire substrates at 600–850 °C. Highly textured SrTiO3films with a [111] orientation were obtained at a growth temperature of 800 °C. The growth parameters which influenced the composition, phase stability, morphology, and texture of the thin films were examined.

ISSN:0021-8979    

DOI:10.1063/1.345034

出版商:AIP    

年代:1990

数据来源: AIP

摘要:

Measurements of wafer surface temperature during plasma etching, performed with a new optical contactless thermometer method, are presented. The respective effects of ion bombardment and chemical reaction on the increase in wafer temperature during plasma etching are evaluated separately. The time dependence of the silicon surface temperature is shown, as a function of the ion bombardment energy and flux on the surface, for both rf and dc applied biases on the wafer. Sample heating resulting from the exothermic chemical reaction of silicon etching by fluorine is demonstrated.

ISSN:0021-8979    

DOI:10.1063/1.345009

出版商:AIP    

年代:1990

数据来源: AIP

摘要:

Previous studies by various researchers show the influence of material shape ofn apparent permeability at zero frequency and predict that this will still be valid at higher frequencies. In this paper we demonstrate the influence of shape demagnetizing effects for the attenuation of transverse electromagnetic waves in a stripline transmission line at frequencies where the material thickness is small compared to the free‐space wavelength in the frequency range 100–600 MHz.

ISSN:0021-8979    

DOI:10.1063/1.345010

出版商:AIP    

年代:1990

数据来源: AIP

摘要:

Low resistance nonalloyed ohmic contacts ofe‐gun evaporated Pt/Ti to S dopedn‐InP 5×1017, 1×1018, and 5×1018cm−3have been fabricated by rapid thermal processing. The contacts to the lower doped substrates (5×1017and 1×1018cm−3) were rectifying as‐deposited as well as after heat treatment at temperatures lower than 350 °C. Higher processing temperatures stimulated the Schottky to ohmic contact conversion with minimum specific contact resistance of 1.5×10−5and 5×10−6&OHgr; cm2, respectively, as a result of rapid thermal processing at 450 °C for 30 s. Heating at a temperature of 550 °C again yielded a Schottky contact. The contact to the 5×1018cm−3InP was ohmic as deposited with a specific contact resistance value of 1.1×10−4&OHgr; cm2. Supplying heat treatment to the contact caused a decrease of the specific contact resistance to a minimum of 8×10−7&OHgr; cm2as a result of rapid thermal processing at 450 °C for 30 s. In all cases, this heat treatment caused a limited interfacial reactions between the Ti and the InP, and resulted in an almost abrupt interface. Heating at temperatures higher than 500 °C resulted in an interfacial intermixing and a mutual migration and reaction of the Ti and the semiconductor elements. The Pt/Ti bilayer structure was highly tensile as deposited (5×109dyn cm−2) and became stress‐free as a result of the interfacial reactions which took place while heating the samples to temperature of 400 °C or higher.

ISSN:0021-8979    

DOI:10.1063/1.344986

出版商:AIP    

年代:1990

数据来源: AIP

摘要:

An alternative approach to obtain the acoustic material signature in scanning acoustic microscopy as the periodicity of the output voltage in the frequency domainV( f ) is suggested. Certain advantages of this technique over the conventionalV(z) approach are demonstrated through experimental results.

ISSN:0021-8979    

DOI:10.1063/1.344987

出版商:AIP    

年代:1990

数据来源: AIP

摘要:

We have measured the strength of the first‐derivative peak observed below the band gap in photoreflectance spectra of semi‐insulating GaAs and found that it is correlated with the bulk residual acceptor concentration. The apparent energy separation of the impurity peak is not fixed, but varies from sample to sample.

ISSN:0021-8979    

DOI:10.1063/1.344988

出版商:AIP    

年代:1990

数据来源: AIP

摘要:

Unstable resonator lasers with a scraper mirror as output coupler suffers from diffraction effects associated with uniformly illuminated aperture. The near‐field intensity distribution is annular in shape with minima at the center. In this communication, a modified resonator is suggested in which the resonator is folded and the scraper mirror is replaced by a partially transmitting mirror to provide the output coupling. The modified resonator is applied to a copper vapor laser. Observed near‐field distribution is uniform across the beam and the intensity of the diffraction rings in the far‐field profiles is considerably reduced.

ISSN:0021-8979    

DOI:10.1063/1.344989

出版商:AIP    

年代:1990

数据来源: AIP

摘要:

All‐optical limiting and bistability are experimentally demonstrated in zinc sulfide waveguides excited by distributed grating couplers. The results are consistent with the presence of a diffusive nonlinearity through the optothermal effect, and a simplified model of the nonlocal traveling‐wave interaction between radiation and guided modes is in agreement with the experimental data.

ISSN:0021-8979    

DOI:10.1063/1.344990

出版商:AIP    

年代:1990

数据来源: AIP

摘要:

The steady‐state mobility‐lifetime products (&eegr;&mgr;&tgr;) and photoconductivity spectra ofa‐Si:H anda‐SiGe:H films with band gaps from 1.74 to 1.10 eV have been determined. The importance of obtaining the bulk &eegr;&mgr;&tgr; at an appropriate wavelength for films of differing compositions and absorption spectra is demonstrated. We show that &eegr;&mgr;&tgr; measured at a wavelength such that the absorption‐thickness product is unity (&agr;t=1) is proportional to the standard photoconductivity measured at one sun illumination for films having a wide range of band gaps and deposition conditions.

ISSN:0021-8979    

DOI:10.1063/1.344991

出版商:AIP    

年代:1990

数据来源: AIP

摘要:

We have utilized rf glow discharge hydrogenated amorphous silicon (a‐Si:H) to build detectors in sandwich geometry with response times in the ps region. Analyzing the shape of the pulses recorded with a sampling head, carrier relaxation times and drift times were obtained. A transition from relaxation time limited to drift time limited response was observed by increasing the bias voltage. Carrier relaxation times and drift mobilities were determined as 460 ps and 0.2 cm2/V s, respectively, the shortest drift time limited response was below 80 ps.

ISSN:0021-8979    

DOI:10.1063/1.344992

出版商:AIP    

年代:1990

数据来源: AIP