摘要:

A novel structure superlattice avalanche photodiode is proposed. Ap‐InGaAs photoabsorption layer is separated from a nondoped InGaAs/InAlAs superlattice avalanche multiplication region. The electric field strength at the photoabsorption layer is controlled by a thin, highly dopedp‐InGaAs layer, which is sandwiched between the multiplication and photoabsorption layers. Devices with this structure were fabricated by molecular beam epitaxy. The external quantum efficiency is 73% at the multiplication factor of unity. The multiplication noise is quite small corresponding to an effective ionization rate ratio of 0.1. The maximum 3 dB bandwidth is 9.3 GHz.

ISSN:0003-6951    

DOI:10.1063/1.104004

出版商:AIP    

年代:1990

数据来源: AIP

摘要:

The kinetics of interstitial iron precipitation inp‐type silicon are investigated. During annealing, the iron charge state is controlled by the applied reverse voltage and its effect on the precipitation is studied. We observe that iron in the neutral charge state (Fe0i) precipitates preferentially in three‐dimensional nucleation centers while Fe+ivanishes in the dislocation lines (rod‐like nucleation centers). These centers are created during the fast cooling procedure necessary to dissolve iron in the silicon matrix.

ISSN:0003-6951    

DOI:10.1063/1.104005

出版商:AIP    

年代:1990

数据来源: AIP

摘要:

We report the successful fabrication of ZnSep‐njunction light‐emitting diodes in which Li and Cl are used asp‐type andn‐type dopants, respectively.

ISSN:0003-6951    

DOI:10.1063/1.104006

出版商:AIP    

年代:1990

数据来源: AIP

摘要:

Improvement of the electrical characteristics of polycrystalline silicon (polysilicon) contactedn+‐pdiodes after application of a forward bias stressing is reported. The improvement existed for diodes whose emitter‐implanted doses of arsenic were larger than 6×1015cm−2for HF‐dipped devices, and 1×1016cm−2for H2SO4heat‐treated devices. The improvement is believed to be due to the neutralization by arsenic of dangling bonds at polysilicon grain boundaries and at the poly/mono silicon interfaces during the stressing process.

ISSN:0003-6951    

DOI:10.1063/1.104007

出版商:AIP    

年代:1990

数据来源: AIP

摘要:

Diamond films have been in‐diffused with lithium in an effort to producen‐type diamond by interstitial doping. Although lithium incorporation was established, only small changes in electrical conductivity and no thermionic emission from donor levels, which should lie only a few tenths of an electron volt below the vacuum level, were observed. To account for these observations, studies of the spectral dependence of external photoemission of lithium‐doped and undoped films were undertaken. These indicate that the lithium donors are compensated by high densities of acceptor states distributed over several electron volts. This first, direct observation of band‐gap states in diamond films accounts for a number of reported properties including their relatively high electrical conductivity and small field effect.

ISSN:0003-6951    

DOI:10.1063/1.104008

出版商:AIP    

年代:1990

数据来源: AIP

摘要:

A differential reflectance (DR) technique has been used to study InGaAs/GaAs and AlGaAs/GaAs quantum wells. DR was measured on ‘‘as‐grown’’ layers, relying solely on the spatial variation of the quantum well parameters for the differential reflectance signal. The DR spectra of AlGaAs/GaAs and InGaAs/GaAs quantum wells exhibited sharp structures corresponding to the anticipated light and heavy hole excitons. The signal‐to‐noise ratio of the DR spectra was considerably better than the photoreflectance spectra measured on the same samples. We concude that DR is an effective and practical technique at room temperature for the study and characterization of semiconductor quantum wells and superlattices.

ISSN:0003-6951    

DOI:10.1063/1.104009

出版商:AIP    

年代:1990

数据来源: AIP

摘要:

Low‐resistance ohmic contacts of Pt/Ti top‐InGaAs/n‐InP heterostructures were formed by rapid thermal processing (RTP). Deep level transient spectroscopy and current‐voltage temperature (I‐V‐T) measurements were used to characterize this system in order to evaluate the stability of the Pt/Ti ohmic contact and the effects of different RTP temperatures on the device performance. A new hole trap level with activation energy of 0.89 eV was found in samples treated at temperatures above 500 °C but not in those treated at lower temperatures. This trap, featured by a higher density when closer to the junction, was thought to be caused by Ti interdiffusion at high RTP temperature, in agreement with the analysis from Auger depth profiling. Four electron trap levels with activation energies of 0.61, 0.45, 0.35, and 0.30 eV were observed for all samples and believed to be native defects in InP.I‐V‐Tmeasurements revealed current mechanisms independent of the RTP temperatures indicating that the new hole trap does not influence current conduction mechanisms.

ISSN:0003-6951    

DOI:10.1063/1.104010

出版商:AIP    

年代:1990

数据来源: AIP

摘要:

The growth of diamond films on various polycrystalline metal and (001) Si substrates by biased hot‐filament chemical vapor deposition is discussed. The deposited films have been characterized by scanning electron microscopy, x‐ray diffraction, Auger electron spectroscopy, and Raman spectroscopy. Films grown on Si, Ni, and W exhibited the best quality according to Ramansp3/sp2peak intensity ratios and the full width at half maximum of the 1332 cm−1Raman peak. The relationship between this quality and substrate properties such as surface energy and lattice parameter is discussed. Also, the residual stress in the film as measured by the Raman peak shift is correlated with the thermal expansion coefficient of the substrate.

ISSN:0003-6951    

DOI:10.1063/1.104011

出版商:AIP    

年代:1990

数据来源: AIP

摘要:

We have studied the properties of metal‐oxide‐semiconductor (MOS) structures fabricated by remote plasma‐enhanced chemical vapor deposition of SiO2upon GaAs substrates. Forn‐type GaAs, a silicon interlayer has been found to improve the interface properties. For our samples and this interlayer, integration of the quasi‐static capacitance curve indicates a band‐bending range of about 0.8 eV. For these samples, we observe a hysteresis of ∼0.6 V, and shifts of only 0.2 V in the midpoint of the rise from minimum to maximum capacitance upon changing frequency from 10 to 200 kHz at room temperature. Similar measurements for temperatures down to 80 K establish that even at such low temperatures an accumulation capacitance is observed. This sets an upper limit of about 70 meV for the separation between the interface Fermi level and the conduction‐band minimum. This limit is a factor of two smaller than the best previously reported limit for approach to the conduction band of GaAs in a MOS structure. Spectroscopic ellipsometry establishes that nearly 2 A˚ equivalent thickness of unoxidized silicon is at the SiO2/GaAs interface.

ISSN:0003-6951    

DOI:10.1063/1.104012

出版商:AIP    

年代:1990

数据来源: AIP

摘要:

The band gap of Ga0.5In0.5P is reported as a function of growth rate and growth temperature. The Ga0.5In0.5P is grown lattice matched to 2°‐off (100) GaAs substrates by atmospheric pressure organometallic chemical vapor deposition using an inlet group V/III ratio of 65. The variation of the band gap is surprisingly complex, taking five different functional forms within the two‐dimensional parameter space. These include regions in which the band gap (1) increases with growth rate, (2) decreases with growth rate, (3) is independent of both growth rate and temperature, (4) is independent of growth rate, but dependent on growth temperature, and (5) is not measurable since three‐dimensional, instead of two‐dimensional, growth is observed. The behavior can only be explained by a theory involving competing processes. One such theory is described.

ISSN:0003-6951    

DOI:10.1063/1.104013

出版商:AIP    

年代:1990

数据来源: AIP