National Semiconductor Corporation

David Tsuei

Alexander H Owens

Peter J Hopper

Vladislav Vashchenko

Peter B Johnson

Yuri Mirgorodski

Andy Strachan

Douglas Brisbin

Chin Miin Shyu

An LDMOS structure which provides for reduced hot carrier effects. The reduction in hot carrier effects is achieved by increasing the size of the drain region of the LDMOS relative to the size of the source region. The larger size of the drain region reduces the concentration of electrons entering the drain region. This reduction in the concentration of electrons reduces the number of impact ionizations, which in turn reduces the hot carrier effects. The overall performance of the LDMOS is improved by reducing the hot carrier effects.

LDMOS transistor structure for improving hot carrier reliability

A method for making an electrically programmable and erasable memory cell is disclosed. Specifically, a method for creating a floating gate using shallow trench isolation-type techniques is utilized to provide a floating gate having sharply defined tip characteristics. A first insulating layer is formed over a substrate. A conductive material is formed over the first insulating layer. A trench is defined in the conductive layer. This trench is filled with an oxide which is used as a mask to define tips of the floating gate during an etching process which defines the edges of the floating gate. After the floating gate has been etched, a tunneling oxide deposited over the floating gate. A conductive material is then formed over the tunneling oxide.

Method of using trenching techniques to make a transistor with a floating gate

In a ESD protection clamp, breakdown and triggering voltage of the structure are reduced by introducing an internal zener diode structure that has a lower avalanche breakdown than the p-n junction of the ESD device. This introduces extra holes into the source junction region causing electrons to be injected into the junction and into the drain junction region to increase the carrier multiplication rate to increase the current density and lower the triggering voltage and breakdown voltage of devices such as NMOS devices or LVTSCRs.

ESD protection clamp with internal zener diode

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Sunnyvale, CA, United States of America

David Tsuei