Method for improving erasing speed of SONOS (Silicon Oxide Nitride Oxide Silicon) by utilizing strained silicon technology

Abstract

The invention discloses a method for manufacturing a SONOS unit transistor with high erasing and writing speed. It is characterized in that after forming the sidewalls of the gate on a P-type substrate that forms several shallow trench isolation areas, it also includes the following steps: 1. Precipitate a barrier layer to cover the transistor; Step 2, etch and remove the barrier layer covering the NMOS area to expose the NMOS area; Step 2, etch the silicon in the active areas on both sides of the gate electrode of the NMOS area; Step 3: Precipitate silicon carbide in the active area through a selective epitaxial process; Step 4: Perform high-temperature annealing to cause the silicon carbide to generate tensile stress on the channel. The energy band of silicon is split. The result of the split is that the effective mass of electrons along the channel direction is reduced. At the same time, the energy valley scattering probability of electrons is also reduced, which significantly increases the electron mobility of the SONOS unit transistor, thus improving the hot electron injection mechanism. SONOS programming efficiency and speed.

Description

technical field [0001] The invention relates to a silicon-silicon oxide-silicon nitride-silicon oxide-silicon (SONOS) memory, in particular to a method for improving the erasing and writing speed of the SONOS by utilizing strained silicon technology. Background technique [0002] The basic working principle of non-volatile semiconductor memory is to store charge in the gate dielectric of a MOSFET. Devices in which charges are stored in discrete trapping centers in a suitable dielectric layer are called charge-trapping devices. The most common of these devices is silicon-silicon oxide-nitride-silicon oxide-silicon (SONOS) memory. [0003] The main two storage mechanisms for storing data in flash memory cells are channel hot electron (CHE) injection and F-N tunneling. Channel hot electron injection is considered to be quite reliable after long-term cycling because it does not place significant stress on the tunnel oxide. But the disadvantage of CHE is that the programming e...

AI Technical Summary

Problems solved by technology

When some electrons get enough high energy, hot electron injection occurs, but since only a small part of the channel is effective for programming, hot electron injection programming is not efficient

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