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Conditions for the formation of defect-induced bound exciton (DIBE) emissions in GaAs were investigated by molecular beam epitaxial method. Growth was made on both A- and B-polarity substrates with (321), (221), and (211) orientations. For A-polarity samples, (321)A and (211)A presented pronounced DIBE emissions. (221)A, however, exhibited no DIBE emission, instead it presented a dominant carbon donor-carbon acceptor pair emission together with a small hump due to carbon donor-related bound exciton emissions. For B-polarity specimens, DIBE was completely vanished in all the three samples. It was theoretically demonstrated that DIBE is formed only when double-handed Ga adatom site is existing.

This paper outlines the defect reduction measures performed during the development of a 130-nm Cu dual-damascene process. The test methodology, using short-loop test structures, included defect tracing, overlaying defect data and electrical measurement data, physical analyses based on these results, and analyses of defect size distribution. While the defect size distributions for large-scale integration processes are considered to depend on , the distribution for the Cu dual-damascene process is found to be different and is instead characterized by a cumulative distribution described by the composition of several Lorentzian functions. Using these procedures, defect densities were successfully reduced by 50% in half the time taken previously and without the need for actual products.

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Molecular beam epitaxy (MBE) of Ge-doped GaAs was made, in which As4 to Ga flux ratio :γ and Ge concentration :[Ge] were used as growth parameters. Photoluminescence (PL) spectra at 2K for slightly Ge-doped GaAs revealed that for γ =1 the emission of excitons bound to neutral Ge acceptors (A°,X) was the dominant one. With increasing γ ,(A°,X) was found to be steeply suppressed and at around γ=1.1, (A°,X) was totally quenched. For γ higher than 1.4, the emission of excitons bound at neutral Ge donors (D°,X) was gradually enhanced and for γ =11, (D°,X) became the principal one. Through van der Pauw measurements, samples with [Ge] around 1×1017cm-3 presented type conversion at around γ=1.7. In this series, the sample with γ =1.0 indicated a strong specific emission, [ g-g], which is formed just below (A°,X) and exhibited a strong energy shift towards lower energy sides (red shift) with increasing [Ge]. [g-g] was theoretically attributed to the pairs between excited-state acceptors. Since [g-g] is known to be easily quenched by small amount of donors, the formation of predominant [g-g] for γ =1 assures that very low-compensated p-type GaAs were grown by using this typically am-photeric impurity. We fabricated a series of p-type Ge-doped GaAs by keeping γ =1 in which the net hole concentration, │ NA-ND │ as high as 1×1020cm-3 was attained. We found four emissions which exhibited significant energy shifts with increasing │ NA-ND │ . From │ NA-ND │ ~1×1016 cm-3, [g-g] begins to appear as a dominant emission and at │ NA-ND │ ~ 1×1017 cm-3, another red shift emission, [g-g]2 begins to be formed parralelly on the higher energy side of [g-g]. It is interesting to note that both [g-g] and [g-g]2 seem to be totally quenched by the further increase of [Ge]. The emission due to band to Ge acceptor,(e,Ge) does not change its central energy until [Ge]= 5×-1018cm-3 and for larger [Ge] it turned into a new broad emission,[g-g]β showing a steep red energy shift. [g-g]α was formed on the higher energy side of (e,Ge) and indicated a systematic blue energy shift with growing [Ge] larger than 1×1019cm-3. [g-g]α was theoretically explained to be the emission due to the pairs between ground-state acceptors.