摘要:

Epitaxial Al Schottky barriers were grown on molecular beam epitaxy AlxGa1−xAs layers without exposure to air. Al is deposited on As‐rich surfaces of AlxGa1−xAs form AlAs interfacial layers modifying the intrinsic Shottky barrier height. The difference between In‐AlGaAs and Al‐AlGaAs barrier heights agree well with their work function difference. Shottky barriers prepared on AlGaAs surfaces with the lowest As‐coverage obey the common anion rule in the regionx⩽0.3. Above this value oxygen‐related elements appear to dominate.

ISSN:0003-6951    

DOI:10.1063/1.92461

出版商:AIP    

年代:1981

数据来源: AIP

摘要:

A new, capless annealing technique for GaAs, which utilizes a controlled‐excess arsenic vapor pressure has been studied. The excess arsenic vapor is provided by the thermal decomposition of InAs and is about 100 times larger than the arsenic pressure of thermally decomposing GaAs for temperatures of 800–900 °C. This excess pressure forces Si implants to activate predominantly on donor sites for doses of (2–50)×1012cm−2studied thus far. A SiF+ dose of 5×1012cm−2and implant energy of 250 keV annealed at 900 °C for 30 min produced a sheet electron concentration of 3.5×1012cm−2and mobility of 4400 cm2V−1sec−1. Photoluminescence studies show that the annealed surfaces must be proximate during anneal to avoid buildup of impurities at the surface. A model based on GaAs evaporation and buildup of bulk impurities on the surface is proposed to explain the results.

ISSN:0003-6951    

DOI:10.1063/1.92462

出版商:AIP    

年代:1981

数据来源: AIP

摘要:

Morphological instability occurring during high‐velocity Si crystal growth from an impurity containing melt is examined in detail. The experimental conditions are achieved by annealing an ion‐implanted Si layer with pulsed laser radiation. Computer modeling is employed to understand the heat flow and impurity diffusion behavior that occurs. The stability and size of impurity segregation cells observed to occur under particular conditions are related to the predictions of morphological stability theory.

ISSN:0003-6951    

DOI:10.1063/1.92470

出版商:AIP    

年代:1981

数据来源: AIP

摘要:

Sequential absorption of two laser photons converts a Cs atomic beam into a ’’cold’’ Cs+ion beam, i.e., a beam with minimal random kinetic energy [Appl. Phys. Lett. 36, 495 (1980)]. Improvements have now increased the spectral brightness by 2.7×104times, i.e., to 2.7 A/cm2 sr eV, and have thereby made this source practical for ion microscopy and similar experiments requiring high‐brightness beams with minimal energy spread.

ISSN:0003-6951    

DOI:10.1063/1.92471

出版商:AIP    

年代:1981

数据来源: AIP

ISSN:0003-6951    

DOI:10.1063/1.92513

出版商:AIP    

年代:1981

数据来源: AIP