Intel Corporation

Simon Y Wang

Daniel N Tang

Simon M Tam

Stefan K Lai

Baylor B Triplett

Himanshu Choksi

Susan L Kao

A method of reducing the degradation effects associated with avalanche injection or tunnelling of hot-electrons in a field-effect semiconductor device is disclosed. The method of the present invention includes covering the active regions of the semiconductor device with a protective titanium barrier layer which is deposited directly underneath the ordinary metalization layers used for connecting the devices to bit and word lines within an array. Inclusion of the titanium barrier layer in a flash memory device results in a substantial improvement in the erasetime push-out and reduces excess charge loss normally associated with hot-electron devices.

Method of reducing hot-electron degradation in semiconductor devices

A method for growing tunnel oxides on a specially treated substrate surface. The method comprises steps for roughening the substrate surface to induce low tunneling voltage in the subsequently grown tunnel oxide layer. The tunnel oxide layer is grown in a low temperature steam cycle to further provide enhanced tunneling. The surface treatment comprises the steps of growing a first oxide layer to seal the surface of the substrate followed by growing a second oxide on the first oxide layer. In the preferred embodiment, a plasma etch utilizing an oxide etcher with high energy ion bombardment and an aluminum electrode is utilized to etch through the first and second oxide layers. The aluminum electrode causes sputtered aluminum on the second oxide layer's surface. The sputtered aluminum blocks the anisotropic etching leaving a grass type oxide residue on the substrate surface. The etching continues, overetching into the substrate surface. The grass type oxide residue causes pitting to occur on the substrate surface. This pitting, resulting in sharpened features on the surface, yields enhanced tunneling characteristics for a subsequently grown tunnel oxide layer. The residue is then removed and the surface cleaned. The tunnel oxide layer is grown in a low temperture steam cycle to preserve and enhance the sharp tips for the purpose of enhanced tunneling.

Field enhanced tunnel oxide on treated substrates

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Sunnyvale, CA, United States of America

Simon Y Wang