Search

A capacitorless cell with only 2 terminals is presented for high-density dynamic random access memory applications. Experiments and calibrated simulations were conducted, which prove that this memory cell has high operation speed (ns level), large read current margin (a read current ratio of 104), low process variation, good thermal reliability and available retention time (190ms). Furthermore, the memory cell is compatible with CMOS technology and free of cyclic endurance problem induced by hot-carrier injection due to the gateless structure.

A new SRAM structure using 2-port PNPN diodes as memory cells is proposed in this article. The electrical characteristics of this memory cell is analyzed and then optimized to meet design requirements. Device fabrication using a simple process flow is conducted. The experimental result and further mixed-mode simulations proved that this diode is feasible for SRAM circuit in advanced VLSI applications.

Detection of rare, circulating tumor cells (CTC's) in human peripheral blood is a potential indicator of prognosis and diagnosis in oncology. Typical methods to detect these CTC's are either by immunocytochemistry (ICCS) or RT‐PCR. However without accurate, rapid, and reproducible enrichment processes, these detection techniques are labor intensive and/or unreliable. In this article, a repeatable enrichment process that included a flow‐through immunomagnetic cell separation system, the quadrupole magnetic sorter (QMS) was optimized with the aid of a statistical analysis software package. The QMS was operated in a negative mode of operation by immunomagnetically targeting normal human peripheral blood lymphocytes (PBL) through the CD45 surface marker. Three head and neck squamous carcinoma cell lines (HNSCC), Detroit‐562, SCC‐4, and CAL‐27, were used to determine the sensitivity of RT‐PCR for the epidermal growth factor receptor (EGFR) in spiked PBL. The detection purity needed for detection was found to be one cell in 104, one cell in 103, and one cell in 105 for the Detroit‐562, SCC‐4, and CAL‐27, respectively. The actual number of cancer cells needed for RT‐PCR detection ranged from 30 to 1 cell. To mimic the potential concentration of rare CTC present in peripheral blood of cancer patients, the spiking concentration was chosen to be one cancer cell per 105 total leukocytes from healthy donors. Using a single step immunomagnetic labeling, the final, optimized enrichment process produced a 57.6 ± 30.3‐fold (n = 6) enrichment of the rare cancer cells with a final cancer cell recovery of (77.8 ± 6.6)%. © 2007 Clinical Cytometry Society

A polydisperse model is established to describe the hydrodynamic behaviors of solid particles within an expanded‐bed adsorption column. This model has been used to simulate bed expansions conducted by different researchers under various operating conditions, and good agreements are found between the experimental and simulated results. The model is effective in simulating not only the change of bed height with fluid velocity, but also the size distributions of solid particles at different axial positions. Due to nonuniform flow in the column and density distribution of the particles, the calculated bed voidage is somewhat different from the measured one for the bottom and top regions of the column.

A capacitorless cell with only 2 terminals is presented for high-density dynamic random access memory applications. Experiments and calibrated simulations were conducted, which prove that this memory cell has high operation speed (ns level), large read current margin (a read current ratio of 104), low process variation, good thermal reliability and available retention time (190ms). Furthermore, the memory cell is compatible with CMOS technology and free of cyclic endurance problem induced by hot-carrier injection due to the gateless structure.

A novel SRAM cell expected to increase the SRAM integration density is proposed and demonstrated with a test structure in this work. It consists of three elements: a MOSFET, a load, and a bistable PNPN diode as the storage element. The PNPN diode and the load can be integrated in a vertically stacked structure, which can be scaled as small as the design rules allow, and the MOSFET has a small gate width, so the new SRAM cell offers the possibility for much higher integration density compared to the conventional 6-T SRAM cell. Moreover, the low holding current of the PNPN diode and the soft “punch-through” design provide the potential for low power consumption and high speed applications.

A new SRAM structure using 2-port PNPN diodes as memory cells is proposed in this article. The electrical characteristics of this memory cell is analyzed and then optimized to meet design requirements. Device fabrication using a simple process flow is conducted. The experimental result and further mixed-mode simulations proved that this diode is feasible for SRAM circuit in advanced VLSI applications.