Low Voltage Protective Diode
Original Publication Date: 1969-Apr-01
Included in the Prior Art Database: 2005-Mar-05
Publishing Venue
IBM
Related People
Abstract
This is a method for lowering the breakdown voltage of a thin-film diode used in a protective electrical circuit, is desired. The method does not significantly change the present processes for making such diodes.
Low Voltage Protective Diode
This is a method for lowering the breakdown voltage of a thin-film diode used in a protective electrical circuit, is desired. The method does not significantly change the present processes for making such diodes.
In drawing 1, protective diode 2 comprises silicon substrate 4 into which is diffused thin layer 6 of arsenic, phosphorus or the like, to produce an N-region. Thin oxide layer 8 is deposited to cover the N-region and over such layer 8 is deposited thin aluminum layer 10. Battery 12 provides a bias to the PN junction produced in the vicinity of the diffused area.
While the curved portions 14 and 16 tend to lower the breakdown voltage of a diode, such voltage can be further lowered by diffusing the arsenic, phosphorus or other diffusant through mask 18 as in drawing 2. When mask 18 of the configuration shown is used, sharp corners 20 are produced in the diffusion layer beneath the thin oxide. These sharp corners play a role similar to any pointed electrode and cause the diode to break down at reduced voltages.
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