We propose a new 2T mask read only memory (ROM) with dynamic column source bias control technique, which enables achieving both high-speed operation and low power consumption. It is also possible to overcome the inherent problem of crosstalk between the bitlines. The fabricated 128-kb ROM macro using 28-nm high- k and metal-gate CMOS bulk technology realizes 0.72 ns read access time at the typical 0.85-V supply voltage, which is comparable to that of recent high-speed embedded static random access memories. The measured dynamic power dissipation is reduced by 50% compared to the conventional 2T ROM. The standby leakage can also be reduced to half that of conventional macros.

We discuss dynamic read and write stabilities of embedded SRAMs in 28-nm high-k/metal-gate (HK/MG) bulk CMOS technology. Test chips which include 1-Mbit single-port SRAM and 512-kbit dual-port SRAM macros are designed and fabricated. A Good correlation for minimum operating voltage (Vmin) between simulation and measurement is observed. We also introduce the test screening circuitry which takes the dynamic stability into consideration. We obtain the appropriate screening results from the evaluations of the testchip. It is also confirmed assured screening with 2.0% dynamic stability fault detection for an SoC product.

6T-SRAM cells in the sub-100 nm CMOS generation are now being exposed to a fatal risk that originates from large local Vth variability (/spl sigma//sub v/spl I.bar/Local/). To achieve high-yield SRAM arrays in presence of random /spl sigma//sub v/spl I.bar/Local/ component, we propose worst-case analysis that determines the boundary of the stable Vth region for the SRAM read/write DC margin (Vth curve). Applying this to our original 65 nm SPICE model, we demonstrate typical behavior of the Vth curve and show new criteria for discussing SRAM array stability with Vth variability.

This paper presents a three-dimensional (3-D) numerical surface diffusion model of BPSG glass flow of surface tension. The analysis region is divided into small cubic cells. Material surface is described as an equi-concentration (equi-existence rate) area which is obtained by linear interpolation between the cells. 3-D surface curvature is defined as the ratio of the increment of surface area to that of volume in a small interface area. Flux of flow is proportional to gradient of the surface curvature, and the direction is from positions of larger curvature to that of small curvature. The flow algorithm is that particles move from the mass-center of the equi-concentration area of a cell to that of the neighbor cells across the contact lines of the cell boundary and the equi-concentration area. This paper presents two 3-D simulations of flow which show that this model can be applied for not only cylindrical symmetry but also general 3-D topography. Also, the surface diffusion coefficient for the total concentration (C/sub imp/: P/sub 2/O/sub 5/ and B/sub 2/O/sub 3/) is derived using the model by fitting 2-D simulations to the experiments at 850/spl deg/C.>