Surface-normal couplers are indispensable parts of a guided-wave optoelectronic interconnects for the coupling of optical signals into and out of the waveguides while facilitating the packaging. In this paper, integration of the 45/spl deg/ surface-normal couplers at each fanout end of the H-tree waveguide structure is described. An optical clock signal distribution system is under development using polyimide based H-tree waveguide structure. The coupler is a 45/spl deg/ slanted end surface of the polyimide waveguide. The coupler works for a wide range of wavelength. The experimentally estimated output coupling efficiency is nearly 100%. To determine the optimized size and shape of the photodetector, near and far field diffraction patterns are evaluated. Experimental results conclude that the phenomenon is dominated by the fundamental mode of the highly multimode waveguide.
Copying the two-step-annealing procedure in self-aligned silicide technology, Ti/Si samples deposited under ultra-high vacuum were annealed at low temperatures, selective etched, and again annealed at high temperatures in our "RHT-6000 rapid heat treatment equipment for VLSI" with nitrogen as the protective ambient. The experimental results showed that titanium silicide and nitride were formed simultaneously in the thin film. The formation of titanium nitride was studied in detail. In addition, we studied the electrical properties of the final product TiN-TiSi/sub 2/ and its diffusion barrier function in the Al/TiN-TiSi/sub 2//Si(n/sup +/p) diode structure.
A novel technique - N2 ion implant followed by vertical high pressure O2 re-oxidation in a furnace, capable of growing oxides of multiple thickness is presented. It is observed that the oxidation rate can be well modulated by varying the N2 I/I dose, and VHP O2 re-oxidation provides enhanced oxide growth rate and controls the nitrogen profile in the film, as compared to RTO or furnace O2 re-oxidation. Therefore, more than 500 percent differential oxide growth rate can be realized by using N2 I/I and VHP O2 re-oxidation. In addition, post-implant RTA N2 anneal is found to improve the channel carrier and alter the flat-band and threshold voltages without increasing the oxide thickness.
This letter correlates fast transient charging (FTC) in high-k gate dielectrics to variations in its oxygen content. Analysis of electrical and physical data suggests that the observed enhancement of FTC may be caused by reduction of the oxygen content in the high-k film due to O scavenging process induced by the HfSi x metal electrode. A hypothesis correlating O scavenging from the high-k dielectric to O vacancy formation, which contributes to FTC, is proposed
Rapid thermal annihilation of microdefects in CZ Si crystals has been studied. The microdefects can be effectively annihilated by RTA for 5/spl sim/60 sec. at temperature over the range of 900/spl sim/1200/spl deg/C. The annihilation of microdefects is not dependent on annealing duration. The concentration of the interstitial oxygen impurities is remarkably increased with microdefect annihilation. It is concluded that the microdefects are involved during RTA process. It is believed that the thermal stress at microdefects induced by RTA is the main cause of microdefect annihilation.
Mo metal gate p-MOSFETs with several advanced gate dielectrics were fabricated. A suitable p-MOSFET work function was achieved and good device characteristics were obtained in all cases. Thermodynamic stability of Mo on Si/sub 3/N/sub 4/, ZrO/sub 2/ and ZrSiO/sub 4/ was verified by good carrier mobility agreement with the universal mobility model.
We report the formation of polyimide-based H-tree waveguides for a multi-GBit/sec optical clock signal distribution in a Si CMOS process compatible environment. Such a clock distribution system is to replace the existing electronic counterpart associated with high-speed supercomputers such as Cray T-90 machine. A waveguide propagation loss of 0.21 dB/cm at 850 nm was experimentally confirmed for the 1-to-48 waveguide fanout device. The planarization requirement of the optical interconnection layer among many electrical interconnection layers makes the employment of tilted grating a choice of desire. Theoretical calculation predicts the 1-to-1 free-space to waveguide coupling with an efficiency as high as 95 percent. Currently, a coupling efficiency of 35 percent was experimentally confirmed due to the limited index difference between guiding and cladding layers. Further experiments aimed at structuring a larger guiding/cladding layer index differences are under investigation. To effectively couple an optical signal into the waveguide through the tilted grating coupler, the accuracy of the wavelength employed is pivotal. This makes the usage of the vertical cavity surface-emitting lasers (VCSELs) and VCSEL arrays the best choice when compared with edge-emitting lasers. Modulation bandwidth as high as 6 GHz was demonstrated at 850 nm. Such a wavelength is compatible with Si-based photodetectors.
The technology and equipment of the infrared rapid thermal annealing for VLSI is reported. The equipment used for rapid thermal annealing has been made with an radio frequency (RF)-induced graphite heater in a quartz housing as an infrared heating source. By using this technology and equipment the fabrication of shallow junction, the formation of silicide, the effect of BPSG reflow and annihilating the micro defects and thermal donor in CZ Si single crystal are discussed.
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