Imec Vzw

Interuniversitair Microelektronica Centrum (imec)

Interuniversitair Micorelektronica Centrum (imec, Vzw)

Interuniversitair Micro-elektronica Centrum Vzw

Ludo Deferm

Jan F Van Houdt

Luc Haspeslagh

Guido V Groeseneken

Herman E Maes

Ricardo Alves Donaton

Mikhail Rodionovich Baklanov

Rita Rooyackers

Philippe Jansen

Rita Verbeeck

Karen Irma Maex

Serge Vanhaelemeersch

Goncal Badenes

Stephan Beckx

Karen Irma Josef Maex

A scaleable device concept and particularly a method for fabrication thereof is disclosed, which allows for a minimal well-controlled gate overlap by using low resistivity source/drain extension regions with shallow junctions. By using such shallow junctions, which are obtained using L-shaped spacers, the gate overlap is no longer dependent on the junction depth of the source/drain contact regions. Particularly the L-shaped spacers are used to locally reduce the penetration depth of the source/drain implantation in the substrate. This concept is particularly interesting for FET's having a channel length below 0.25 &mgr;m because this approach broadens the process window of the silicidation process of the source/drain contact regions. Moreover, the extension regions have to be subjected only to a limited thermal budget.

Method for forming a FET having L-shaped insulating spacers

The present invention is a method for programming SSI cells or an array of said cells. The method achieves very fast programming while consuming only a very small amount of power, which paves the way for new applications such as battery-operated systems, page-mode programming for very high data throughput. The method also allows for the bitline voltage to be increased internally on the chip in order to circumvent the efficiency decrease associated with supply voltage scaling. By exploring the SSI mechanism in the subthreshold regime, an optimum value for the CG voltage is found for which the gate current is no longer maximized, but the energy consumed from the power supply is minimized and the injection efficiency during programming is maximized. The programming of a memory cell in this regime, where the gate current is a very steep function of the CG voltage, is, however, still achieved in a few microseconds while consuming only a very small cell current in the range of nanoamperes. This allows an entire wordline in the array to be programmed simultaneously, even if the supply voltage is scaled down to 3.3V or below. This possibility, combined with a physical programming time per cell which is still very short, realizes an effective programming time in the order of 20 ns/byte for a 1Mbit device, which corresponds to a maximum programming transfer rate of 50 Mbyte/s. State-of-the-art Flash memories typically show a transfer rate in the order of 20-300 Kbyte/s during programming which is 2 to 3 orders of magnitude slower than in the case of the present invention. Therefore, the method of the present invention with the accompanying programming scheme represents a substantial improvement in terms of high-speed-oriented as well as low-power-oriented applications. It is important to mention here that optimizing the injection efficiency instead of the gate current itself, is not a straightforward solution for next generation Flash memories, since the gate current is much more difficult to control due to the steepness of the subthreshold characteristic of the MOS device.

Method of erasing a flash EEPROM memory cell array optimized for low power consumption

The present invention relates to methods for controlling the etching rate of CoSi,layers by adjusting the pH of an HF-based solution to obtain the desired etch rate. The pH of the HF-based solution may be adjusted by adding pH modifying chemicals to the solution. A further aspect of the invention is an improved method for manufacturing Schotky barrier infared detectors employing the controlled etching step. A method for reducing drain induced barrier lowering in an active transistor having a small gate length is also provided.

Etching process of CoSi2 layers

The present invention relates to methods for controlling the etching rate of CoSi.sub.2 layers by adjusting the pH of an HF-based solution to obtain the desired etch rate. The pH of the HF-based solution may be adjusted by adding pH modifying chemicals to the solution. A further aspect of the invention is an improved method for manufacturing Schottky barrier infared detectors employing the controlled etching step. A method for reducing drain induced barrier lowering in an active transistor having a small gate length is also provided.

Etching process of CoSi.sub.2 layers

The present invention relates to methods for fabricating Fully Overlapped Nitride-Etch Defined (Fond) devices. These methods permit the lateral dimension and depth of the lowly-doped source and drain extensions to be independently controlled and well defined.

Fully overlapped nitride-etch defined device and processing sequence

The present invention is a method for programming SSI cells or an array of said cells. The method achieves very fast programming while consuming only a very small amount of power, which paves the way for new applications such as battery-operated systems, page-mode programming for very high data throughput. The method also allows for the bitline voltage to be increased internally on the chip in order to circumvent the efficiency decrease associated with supply voltage scaling. By exploring the SSI mechanism in the subthreshold regime, an optimum value for the CG voltage is found for which the gate current is no longer maximized, but the energy consumed from the power supply is minimized and the injection efficiency during programming is maximized. The programming of a memory cell in this regime, where the gate current is a very steep function of the CG voltage, is, however, still achieved in a few microseconds while consuming only a very small cell current in the range of nanoamperes. This allows an entire wordline in the array to be programmed simultaneously, even if the supply voltage is scaled down to 3.3V or below. This possibility, combined with a physical programming time per cell which is still very short, realizes an effective programming time in the order of 20 ns/byte for a 1 Mbit device, which corresponds to a maximum programming transfer rate of 50 Mbyte/s. State-of-the-art Flash memories typically show a transfer rate in the order of 20-300 Kbyte/s during programming which is 2 to 3 orders of magnitude slower than in the case of the present invention. Therefore, the method of the present invention with the accompanying programming scheme represents a substantial improvement in terms of high-speed-oriented as well as low-power-oriented applications. It is important to mention here that optimizing the injection efficiency instead of the gate current itself, is not a straightforward solution for next generation Flash memories, since the gate current is much more difficult to control due to the steepness of the subthreshold characteristic of the MOS device.

Method of programming a flash EEPROM memory cell array optimized for low

The present invention is a method for programming SSI cells or an array of said cells. The method achieves very fast programming while consuming only a very small amount of power, which paves the way for new applications such as battery-operated systems, page-mode programming for very high data throughput. The method also allows for the bitline voltage to be increased internally on the chip in order to circumvent the efficiency decrease associated with supply voltage scaling. By exploring the SSI mechanism in the subthreshold regime, an optimum value for the CG voltage is found for which the gate current is no longer maximized, but the energy consumed from the power supply is minimized and the injection efficiency during programming is maximized. The programming of a memory cell in this regime, where the gate current is a very steep function of the CG voltage, is, however, still achieved in a few microseconds while consuming only a very small cell current in the range of nanoamperes. This allows an entire wordline in the array to be programmed simultaneously, even if the supply voltage is scaled down to 3.3V or below. This possibility, combined with a physical programming time per cell which is still very short, realizes an effective programming time in the order of 20 ns/byte for a 1 Mbit device, which corresponds to a maximum programming transfer rate of 50 Mbyte/s. State-of-the-art Flash memories typically show a transfer rate in the order of 20-300 Kbyte/s during programming which is 2 to 3 orders of magnitude slower than in the case of the present invention.

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Ludo Deferm