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Schottky Barrier Diode for Substrate Evaluation

IP.com Disclosure Number: IPCOM000086867D
Original Publication Date: 1976-Nov-01
Included in the Prior Art Database: 2005-Mar-03
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Beyer, KD: AUTHOR [+2]

Abstract

Schottky barrier diode (SBD) yields are determined, in part, by bulk defects. It has been found that a 10/11/ atoms per cm/-2/ level of either sodium or potassium are sufficient to adversely affect the forward and reverse SBD characteristics. A yield improvement of unsintered aluminum SBD can be achieved using argon implantation backside gettering. This yield improvement of unsintered aluminum SBD's by backside ion implantation can be attributed to the removal of copper by argon implantation gettering on the wafer backside. A yield improvement of unsintered aluminum SBDs can also be obtained by removing the native oxide layer on the silicon surface by replacing a liquid HF dip by HF/H(2)O vapor etching just prior to the aluminum deposition.

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Schottky Barrier Diode for Substrate Evaluation

Schottky barrier diode (SBD) yields are determined, in part, by bulk defects. It has been found that a 10/11/ atoms per cm/-2/ level of either sodium or potassium are sufficient to adversely affect the forward and reverse SBD characteristics. A yield improvement of unsintered aluminum SBD can be achieved using argon implantation backside gettering. This yield improvement of unsintered aluminum SBD's by backside ion implantation can be attributed to the removal of copper by argon implantation gettering on the wafer backside. A yield improvement of unsintered aluminum SBDs can also be obtained by removing the native oxide layer on the silicon surface by replacing a liquid HF dip by HF/H(2)O vapor etching just prior to the aluminum deposition.

The application of unsintered aluminum SBDs can be used as a tool for substrate evaluations. For an example, a 2 mu thick aluminum metal layer is evaporated on the silicon substrate through a metal evaporation mask which delineates aluminum areas in the kerf area of a semiconductor chip or which deposits aluminum dots of various sizes (5, 10, 20 or 60 mil diameter aluminum dots) on the substrate. The substrate doping has to be N type for aluminum. For P substrates, other metals, such as hafnium, have to be selected.

As in current bipolar processes, an N type epitaxial layer is deposited over P substrate, unsintered aluminum SBDs can be used to evaluate the epitaxial layer in resp...