Volker Hecht

A Novel Flash-based FPGA Technology with Deep Trench Isolation

A highly scalable flash-based Field Programmable Gate Array (FPGA) technology has been achieved with Deep Trench Isolation (DTI). The DTI allows for a reduced cell size and enables Independent Pwell (IPW) array operation. The IPW FPGA array operation requires less than + 10 V during Uniform Channel FN-FN programming and shows negligible gate disturb. Additionally, it eliminates Gate-Induced Drain Leakage (GIDL) during programming. Characterization of a FPGA cell and array with 90 nm design rules is demonstrated with excellent electrical characteristics.

A 65nm flash-based FPGA fabric optimized for low cost and power

This paper describes a non-volatile reprogrammable FPGA fabric, whose configuration data are provided directly by flash memory. The fabric is optimized for low-cost, low-power applications, leveraging the density of flash and the elimination of conventional configuration SRAM and its attendant static power. After surveying the necessary background on flash and its application to FPGAs, the 1T flash cell is described along with relevant novel aspects of the fabric architecture. The addition of a third level of switching between inter-cluster signals and logic inputs helps to reduce area and raise typical utilization above 95%. Despite the longer signal path, performance is maintained by synergism between the improved routing flexibility and extreme minimization of the fastest LUT input delay. Test cost is reduced by built-in circuits that can test all switches without reprogramming the flash memory. The fabric has been implemented in a 65nm CMOS embedded flash process.

Flash-based Field Programmable Gate Array Technology with Deep Trench Isolation

A highly scalable flash-based Field Programmable Gate Array (FPGA) technology has been achieved with Deep Trench Isolation (DTI). The DTI allows for a reduced cell size and enables Independent Pwell (IPW) operation. The IPW allows the Fowler-Nordheim (FN) Uniform Channel Program and Erase (UCPE) with less than plusmn10 V. Additionally, the IPW approach allows a greater flexibility in the array bias scheme reducing the gate disturb during programming and eliminating all Gate-Induced Drain Leakage (GIDL) conditions. Characterization of a FPGA cell and 0.5 Mbit array with 90 nm design rules is demonstrated with excellent electrical characteristics.

Highly Scalable Embedded Flash Memory With Deep Trench Isolation and Novel Buried Bitline Integration for the 90-nm Node and Beyond

In this paper, we embedded a Flash memory cell with 90-nm ground-rules in a high-performance CMOS logic process. A novel deep trench isolation (DTI) module enables an isolated p-well (IPW) bias scheme, leading to Flash with uniform channel program/erase by Fowler-Nordheim tunneling without gate induced drain leakage, a key feature for low-power portable electronics. The IPW concept leads to a compact cell design and a highly scalable high-voltage periphery through the narrow intrawell and interwell isolation spaces. The memory arrays are defined by DTI of each bitline (BL) from its neighboring BLs. We additionally present a buried BL (BBL) concept that links the source contacts of each individual BL via the IPW; thus, effectively eliminating one metal line per BL and reducing overall cell size. A conservative cell size shrink of about 40% can be achieved for a uniform channel program/erase-Flash cell with deep trench and BBL compared to a conventional 21F2cell.