David Dawson-Elli

Group delay and chromatic dispersion of thin-film-based, narrow bandpass filters used in dense wavelength-division-multiplexed systems.

Theoretical analysis is made for thin-film-based, 200- and 100-GHz narrow bandpass filters with respect to the intensity response as well as to the chromatic dispersion. The results indicate that the narrower the passband, the higher the chromatic dispersion. The maximum chromatic dispersion appears at the edges of the 0.5-dB passband, owing to the fast change of the group delay in the region. The deviation of chromatic dispersion induced by manufacturing error is simulated. Effective-medium approximation layers are added to simulate the contribution of surface roughness and the mixture interfaces to the passband ripple as well as the chromatic dispersion. The simulations are compared with the experimental results. The measured chromatic dispersion matches the general trend of the theoretical calculation. The imperfect surface and layer mismatch induce additional ripples across the 0.5-dB passband. The maximum chromatic dispersion within a 0.5-dB passband is 20.7 and 54.9 ps/nm for 200- and 100-GHZ narrow bandpass filters, respectively.

Substrate influences on CIS device performance

It has been reported that the substrate plays an active role in copper indium diselenide (CIS) devices. The physical properties of the substrate, i.e., thermal expansion coefficient, chemical composition, strain point, surface quality and cleanliness may all play a role in device efficiency and process reproducibility. For example, sodium is known to influence the conductivity of CIS, and that soda lime glass (SLG) introduces sodium into the CIS. In the experiments reported here, the sodium level in the CIS was varied by (a) changing the substrate composition and (b) the use of SiO/sub x/N/sub y/ and SiN/sub x/ barrier layers. Solar cells were fabricated on the candidate substrate and barrier layer combinations. V/sub oc/ was observed to drop with the addition of barrier layers to sodium containing glasses. The films were also analyzed for sodium by SIMS. The cell performance and SIMS analysis are presented and their significance is discussed.

Single Fermi Level Thin-Film CMOS on Glass: The Behavior of Enhancement-Mode PMOSFETs From Cutoff Through Accumulation

A device model which describes the behavior of thin-film transistors fabricated in crystalline silicon on glass is introduced. The dc current-voltage characteristics of fully depleted thin-film silicon p-channel enhancement-mode MOSFETs operated in accumulation is provided. Physically derived expressions are presented for drain current in the accumulation and depletion regions which include the correct dependence on drain voltage, film thickness, and doping level. AC-infin model is realized from cutoff to accumulation by using an interpolant around the flatband voltage and a hyperbolic tangent blending function. The device model shows excellent agreement with measured results for output, transfer, and transconductance characteristics. A compact circuit simulation model has also been implemented in the Spectre circuit simulator using Verilog-A.

Low Temperature Dopant Activation for Integrated Electronics Applications

A major area of research for integrated electronic systems is the development of systems on glass or plastic. These alternative substrate materials impose significant constraints on electronic device fabrication, including limitations on chemical and thermal processes. This work presents an investigation on the activation of ion-implanted dopants without using the high temperature processes of conventional CMOS. The annealing temperature applied was 600degC, which could potentially enable integrated microelectronics on high-quality glass. Additional factors studied included the annealing technique (furnace or rapid thermal processing), and the use of pre-amorphization implants. Ion-implant modeling along with SIMS and SRP data was used to develop a comprehensive understanding of the experimental results. The performance of transistors fabricated with low-temperature constraints on both bulk silicon and thin- film SOI was presented.

P-197L: Late-News Poster: Demonstration of High Performance TFTs on Silicon-on-Glass (SiOG) Substrate

This report is an introduction to a new silicon-on-glass (SiOG) substrate and device technology. The fabrication and analysis of CMOS devices fabricated using SiOG are presented. The SiOG devices are comparable to those fabricated on SOI wafers with respect to carrier mobility and off-state leakage current. This technology clearly demonstrates the potential for system-on-panel integration.

Group delay and chromatic dispersion of narrow bandpass filters used in DWDM systems

The chromatic dispersion of narrow bandpass filters for DWDM application is discussed. Theoretical simulations are compared with the experimental results; the deviation of chromatic dispersion induced by manufacturing error is simulated.

Scatter measurements of narrow band pass filters

The scattering behavior for narrow band pass filters processed by ion beam sputtering was evaluated and compared to that of a Corning proprietary process. Results showed no significant difference in scattering for the different processes.