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A new three-dimensional (3D) integration technology for realizing a highly parallel image-processing chip has been developed. Several LSI wafers are vertically stacked and glued to each other after thinning them using this new technology. This technology can be considered as both 3D LSI technology and wafer-scale 3D chip-on-chip packaging technology. The effective packaging density can be significantly increased by stacking the chips in a vertical direction. Several key techniques for this 3D integration have been developed. In this paper, we demonstrate the highly parallel image sensor chip with a 3D structure. The 3D image sensor test chip was fabricated using this new 3D integration technology and its basic performance was evaluated.

Temperature dependence of fine structures in the tunneling conductance of a Bi 2 Cr 1.4 La 0.6 CuO 6−x -GaAs junction was studied. They are attributed to phonons and our previous phonon model is improved.

The epitaxial chemical vapor deposition of SiC on (100) and (111) Si substrates has been conducted in a cold wall furnace from methyltrichlorosilane (MTS) as the single source material. In the temperature range from 1100°C to 1350°C, both surface-reaction-limited growth and diffusion-limited growth have been observed. The activation energy for growth was decreased using a two-step process route in which an intermediate layer was deposited by controlling only the partial pressure of the MTS.

A new three-dimensional (3D) wafer bonding technology using the adhesive injection method has been proposed, in order to realize a real-time micro-vision system and a real shared memory. Several key technologies for 3D LSI, such as deep trench formation for buried interconnection, wafer grinding and chemical-mechanical polishing, wafer alignment and wafer bonding using the adhesive injection method, have been developed.

Phonon structures in the tunneling conductance must be properly normalized to evaluate the intensity of the electron-phonon interaction. However, this is very difficult because of the absence of the exact normal-state conductivity. Therefore we propose another method to judge whether or not the intensity becomes stronger with a critical temperature T c. This method compares the intensity of anharmonic structures, which are normalized to the single-phonon structures, between high- and low-T c substances. Our data for Bi-cuprates strongly suggest that the electron-phonon interaction is stronger in higher-T c substances.

A zero-bias resistance peak appeared in the tunneling resistance curve of Bi-cuprates, Na0.89WO3 and ReO3, contacted with GaAs or SnO2-x . Therefore the peak is not inherent to high-T c superconductors and may not be relevant to the electronic properties in the bulk.

Anisotropy in the energy gap of Bi2212 was investigated by using a point contact tunneling junction and it was noted that there was very little anisotropy. When a GaAs needle was contacted perpendicular to the c -plane, at least two kinds of conductance curves were obtained, one with a gap of 42 meV and the other with a gap of 64 meV. In the latter, phonon structures extended to a higher voltage and a three-phonon process was observed similar to our multiphonon exchange model for superconductivity.

A mismatch in the resistor ratio causes nonlinearity in successive-approximation A/D converters fabricated with a 2^{n}R potentiometric technique. This paper describes a theoretical analysis of this kind of nonlinearity and a method of evaluating the variations in resistance obtained in experiments with monolithic resistors. The resistance variations are classified into a statistically random variation component and a deterministic variation component. The relationship of both components to the nonlinearity error is then clarified. A 7-bit diffused resistor string was fabricated with a silicon-gate NMOS process. An autocorrelation technique was used to identify and separate several resistance variation components in the string. On the basis of the theoretical and experimental results that were obtained, we have developed 10-bit A/D converters and confirmed their accuracy.

We present tunneling results on tri-layered cuprate superconductors TlBa2Ca2Cu3O8.5+δ (Tl1223) with two different hole concentration, which are an over-doped Tl1223 with TC ∼ 112 K (OD-112K) and a slightly over-doped Tl1223 with TC ∼ 126 K (SOD-126K). The tunneling conductances on both samples exhibited two sizes of gaps originated from outer (OP) and inner (IP) CuO2 planes. The superconducting gap at each planes, Δ(OP)/e ≈ Vp(OP) and Δ(IP)/e ≈ Vp(IP) on OD-112K are observed that Vp(OP) is 22 ± 2 mV and Vp(IP) is 37 ± 4 mV. Similarly, Vp(OP) is 26 ± 2 mV and Vp(IP) is 39 ± 3 mV on SOD-126K. Although both Vp(OP) and Vp(IP) decrease with increasing oxygen contents, ΔVp(OP) = Vp(OP)(SOD-126K) - Vp(OP)(OD-112K) is larger than ΔVp(IP) for IP. Moreover, ΔVp(plane) Vp(IP) - Vp(OP) increases with overdoping. These results as a function of doping implies the OP might control the variation of TC dominantly.

A multiphonon exchange model is proposed to explain the high critical temperature and its increase with the number of CuO 2 layers between Bi(Tl) 2 O 2 layers in copper oxides. In this model, the Cooper pair is formed through the exchange of multiphonons on different CuO 2 layers.