摘要:

A new type of chemical vapor deposition method, named ‘‘Catalytic‐CVD’’ method, is presented. In the method, deposition gases are decomposed by catalytic or pyrolytic reaction between deposition gases and a heated catalyzer, and films are thermally grown on a substrate at temperatures lower than 300 °C without any help from glow discharge plasma. Hydro‐fluorinated amorphous silicon (a‐Si:F:H) films are deposited by this method using both a SiF2and H2gas mixture and a SiH2F2and H2mixture. It is found that a very high qualitya‐Si:F:H film can be obtained, and for instance, that the photosensitivity for AM‐1 of 100 mW/cm2exceeds 106and the spin density is as low as 6×1015cm−3.

ISSN:0021-8979    

DOI:10.1063/1.342069

出版商:AIP    

年代:1988

数据来源: AIP

摘要:

The etching reaction of molecular chlorine with phosphorus‐doped polycrystalline silicon was measured as a function of dopant concentration between 300 and 500 °C. The effective activation energy of the gasification reaction is 13.4±1 kcal/molec and does not change with doping level within experimental uncertainty. However, the isothermal reaction rate at constant reactant flux increases sharply with doping level, and the preexponential factor rises from 4×10−12to 1×10−10(A˚ cm3/molec min K1/2) as the phosphorus content is increased from 3.3×1018to 1.6×1020atoms/cm3. This rise in the preexponential factor is consistent with the charge‐transfer model, in which doping makes Si‐Cl bonding more ionic and increases the number of effective adsorption sites.

ISSN:0021-8979    

DOI:10.1063/1.342070

出版商:AIP    

年代:1988

数据来源: AIP

摘要:

A theoretical model is presented for the anodization of silicon in an oxygen plasma. The model is based on the space‐charge‐limited drift of negative oxygen ions through the growing oxide film to react at the silicon‐silicon dioxide interface. In the initial linear growth region the supply of ions from the plasma determines the growth, whilst for longer periods the drift of ions through the oxide gives rise to parabolic growth kinetics. The theory is consistent with the lack of orientation dependence observed for the plasma oxidation of silicon. It is applicable over the whole of the growth kinetics, for anodization in both constant voltage and constant current modes. The dependence of current and voltage with time during anodization may also be predicted. The theory is shown to be applicable to oxide growth occurring in both an inductively coupled, rf‐stimulated plasma and a microwave‐sustained oxygen plasma over a range of experimental conditions.

ISSN:0021-8979    

DOI:10.1063/1.342076

出版商:AIP    

年代:1988

数据来源: AIP

摘要:

Emission mechanisms and reaction rates for the ion‐assisted etching of GaAs(100) have been studied in detail using energetic argon ions and chlorine gas. Ion energies of 500 and 1000 eV were used with chlorine/argon ion surface‐flux ratios of 1–120. Themajormolecular etchant products were found to be GaCl2and AsCl3. Gas phase products were detected at different flight distances to investigate the nature of surface residence times. It is concluded, based on these measurements, that GaCl2emission is best interpreted in terms of the collisional‐cascade sputtering model for the specific range of ion energies and surface‐flux ratios studied. Using a similar analysis, it is concluded that AsCl3may be emitted by either the thermal desorption or the collisional‐cascade mechanisms, with the former favored in the range of higher surface‐flux ratios and lower ion energies. Furthermore, the thermal desorption of AsCl3appears to follow a first‐order surface process. Comparison of our data with those of others indicates general agreement. However, more extended analysis based on a broader and more intensive data base leads to some important distinctions among the final conclusions regarding the emission mechanisms.

ISSN:0021-8979    

DOI:10.1063/1.342479

出版商:AIP    

年代:1988

数据来源: AIP

摘要:

The propagation of the modal voltages and currents is investigated for the transverse magnetic modes having azimuthal variation in a cylindrical waveguide with periodic step changes in the radius. The transfer coefficients are evaluated explicitly for small relative changes in the radius. The theory is applied to treat the selective and coherent coupling between two forward traveling modes.

ISSN:0021-8979    

DOI:10.1063/1.342047

出版商:AIP    

年代:1988

数据来源: AIP

摘要:

We report on a new high‐speed InP‐based InxGa1−xAs Schottky barrier photodiode for infrared detection. The photodiodes were fabricated on bothp‐ andn‐InGaAs epilayers. For this application, Schottky barrier height enhancement on InGaAs has been demonstrated. The photodiodes had responsivities as high as 0.55 A/W and quantum efficiencies of up to 45% in the range of 1.3–1.6 &mgr;m without antireflection coating. The response speed of photodiodes was measured by the impulse response and autocorrelation methods; rise times of 85 ps forp‐InGaAs and 180 ps forn‐InGaAs photodiodes were obtained. Recently, a barrier height enhancement of 0.35 eV was obtained inn‐InGaAs photodiodes, resulting in a great reduction of leakage currents. This would lead to further improvement in the device performance of the photodiodes. Based on measured RC time constants, we estimate the intrinsic response speed to be 12 GHz forn‐InGaAs and 18 GHz forp‐InGaAs photodiodes. These results show that InP‐based InxGa1−xAs Schottky barrier photodiodes can be very useful for high‐speed infrared receivers in fiber‐optic communications.

ISSN:0021-8979    

DOI:10.1063/1.342048

出版商:AIP    

年代:1988

数据来源: AIP

摘要:

This paper presents a general method of calculation, allowing us to deduce the noise equivalent power in any type of avalanche photodiode. This method is checked by comparing numerical and analytical results for the case of ap‐i‐njunction. The calculation is applied to some Ga0.96Al0.04Sb diodes in order to estimate their performance and to deduce some trends for their optimization.

ISSN:0021-8979    

DOI:10.1063/1.342049

出版商:AIP    

年代:1988

数据来源: AIP

摘要:

This paper analyzes a photoconductive switch design utilizing a static magnetic field to displace the optically generated electron‐hole plasma to surfaces having high recombination velocities. It is demonstrated that this mechanism markedly speeds up the turnoff transient of the switch without affecting its conductance in the illuminated steady state.

ISSN:0021-8979    

DOI:10.1063/1.342025

出版商:AIP    

年代:1988

数据来源: AIP

摘要:

The electrical and optoelectronic characteristics of planar InP/InGaAsp‐i‐nphotodiodes grown by metalorganic chemical vapor deposition were extensively investigated. A typical room‐temperature dark current of 10 pA for 100‐&mgr;m‐diam devices was measured at −10‐V bias on several wafers. A low capacitance between 0.42–0.46 pF (for 100‐&mgr;m‐diam devices), responsivities at 1.3 &mgr;m between 0.84–0.94 A/W (corresponding to external quantum efficiencies between 80% and 90%), and rise/fall times of less than 150 ps were measured at −5‐V bias on several wafers. Excellent uniformity in dark current, junction capacitance, and optoelectronic characteristics was found over large wafer areas. The diode dark current was studied as a function of applied voltage, temperature, diode dimensions, and junction depth. The carrier transport mechanisms in different ranges of bias voltage and temperature have been identified and interpreted both in form and magnitude. At low to mid reverse bias, bulk generation‐recombination currents dominate below 320 K. At higher temperatures, diffusion currents become dominant. Band‐to‐band tunneling current near the InP/InGaAs upper heterointerface dominates the dark current at high reverse bias. Under forward bias, the diffusion current dominates over the entire temperature range studied. Theoretical models have been developed to account for the magnitude of the reverse and forward diffusion currents and their dependence on diode dimensions. It is found that the lowest dark current measured at room temperature is very close to the theoretical limit achievable for planar InP/InGaAs/InP diodes withndoping of the InGaAs ∼1×1015cm−3.

ISSN:0021-8979    

DOI:10.1063/1.342026

出版商:AIP    

年代:1988

数据来源: AIP

摘要:

A study of the low‐temperature photoluminescence characteristics of very narrow one‐dimensional quantum‐well structures, grown by atmospheric pressure organometallic chemical vapor deposition, is presented. Theoretically predicted narrowing of photoluminescence peaks as quantum‐well widths approach zero was experimentally observed in both AlGaAs/GaAs and strained GaAs/InGaAs samples. The role of such data in determining interface microstructure is discussed.

ISSN:0021-8979    

DOI:10.1063/1.342027

出版商:AIP    

年代:1988

数据来源: AIP