摘要:

Photoluminescence studies of C+, Mg+, Zn+, and Cd+ion‐implanted GaAs layers were carried out at 2 K. Two conspicuous emissions denoted bygand [g‐g] were observed to be situated between bound exciton and band to acceptor emissions. It was found that these two are common emissions among the above acceptor impurities, and that they can be explicitly observed only when the background impurity concentration is extremely small.

ISSN:0003-6951    

DOI:10.1063/1.96762

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

The role of hydrogen in the creation and annealing kinetics of the light‐induced metastable defects in hydrogenated amorphous silicon is investigated using electron spin resonance. Deuterated and hydrogenated films exhibited the same defect creation rate and nearly identical distributions of annealing energies. Implications of these results for various microscopic models for the creation of metastable defects are discussed.

ISSN:0003-6951    

DOI:10.1063/1.97022

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

A combination of high resolution electron microscopy (HREM), electron energy loss spectroscopy (EELS), energy dispersive x‐ray analysis (EDXA), and scanning transmission electron microscopy (STEM) techniques has been employed to characterize the structure and composition of vapor‐deposited thin films of semi‐insulating polycrystalline silicon (SIPOS) and their interfaces with Si. SIPOS layers containing ∼30 at. % of oxygen are amorphous when deposited at Si substrate temperature of 625 °C. Upon annealing at 900 °C in N2for 30 min, Si crystallites up to ∼100 A˚ in size appear throughout the SIPOS layer, the microstructure of which appears to be a dispersion of Si crystallites in an amorphous matrix. The plasmon‐loss spectra show a characteristic energy for each material: 16.7 eV for Si, 17.6 eV for SIPOS, and 23.2 eV for SiO2, which correlate empirically with increasing oxygen content in these materials. A combination of HREM and STEM revealed the existence of a 25–30‐A˚ native oxide layer between the SIPOS and Si substrate. This native oxide yields a plasmon loss at 22 eV using a 10‐A˚ probe in the STEM.

ISSN:0003-6951    

DOI:10.1063/1.96763

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

We demonstrate for the first time that the phase shift associated with amplitude modulated, near band‐edge photoluminescence from Si at room temperature can be used to map defects and carrier lifetimes over full wafers with depth sensitivity.

ISSN:0003-6951    

DOI:10.1063/1.96764

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

Room‐temperature high‐frequency measurements on a three‐terminal amplifying device based on real‐space hot‐electron transfer between two conducting layers separated by a potential barrier have been performed. The devices grown by organometallic chemical vapor deposition utilize a novel undoped GaAs/AlGaAs heterostructure which, through its dramatically reduced parasitic leakage compared to previous structures, permits, for the first time, operation as a charge injection transistor. The charge injection transistor exhibits true three‐terminal amplification due to real‐space hot‐electron transfer controlled by electron temperature in a high mobility channel. The device demonstrates power and current gains with cut‐off frequencies of 9.8 and 29 GHz, respectively, with maximum current gain of 39 dB. In the negative resistance transistor mode, the same device was found capable of microwave generation up to 7.7 GHz. The frequency response of our device is shown to be limited byRCin the output circuit and methods for improvement of the cut‐off frequency are discussed.

ISSN:0003-6951    

DOI:10.1063/1.96765

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

GaAs space solar cells with areas of 4 cm2have been fabricated by metalorganic chemical vapor deposition. The AlGaAs‐GaAs heteroface structures have been grown in both thep‐nandn‐pconfigurations. Under one sun, air mass zero conditions and at 25 °C, thep‐ncell is characterized by a short‐circuit current density of 32.3 mA/cm2, an open‐circuit voltage of 1.05 V, and a fill factor of 0.84, resulting in a conversion efficiency of 21.1%. The corresponding values forn‐pcells are 33.8 mA/cm2, 1.01 V, and 0.83, resulting in a conversion efficiency of 21.0%.

ISSN:0003-6951    

DOI:10.1063/1.96766

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

Mixtures of poly(methyl methacrylate) and poly(&agr;‐methyl styrene) were prepared and their optical absorption coefficients at 193 nm were measured. A study of photoetching rate of these polymeric materials using an ArF excimer laser at 193 nm shows two regions of distinctly different etching characteristics. At relatively high fluences (>300 mJ/cm2) the photoetch rate decreased with increasing absorption in the polymer films, while at lower fluences, an optimum range of absorption coefficients was found to give the maximum photoetching rate.

ISSN:0003-6951    

DOI:10.1063/1.96767

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

A silicon wafer bonding process is described in which only thermally grown oxide is present between wafer pairs. Bonding occurs after insertion into an oxidizing ambient. It is proposed the wafers are drawn into intimate contact as a result of the gaseous oxygen between them being consumed by oxidation, thus producing a partial vacuum. The proposed bonding mechanism is polymerization of silanol bonds between wafer pairs. Silicon on insulator (SOI) is produced by etching away all but a few microns of one of the bonded pair. Capacitor measurements show a 27 &mgr;s minority‐carrier lifetime and no degradation of the SOI‐insulator interface. In addition, there is negligible charge at the bonding interface making the technique attractive for three‐dimensional as well as planar SOI applications.

ISSN:0003-6951    

DOI:10.1063/1.96768

出版商:AIP    

年代:1986

数据来源: AIP