Browse Prior Art Database

Forming Buried Subcollectors by Ion Implantation

IP.com Disclosure Number: IPCOM000086240D
Original Publication Date: 1976-Aug-01
Included in the Prior Art Database: 2005-Mar-03
Document File: 2 page(s) / 50K

Publishing Venue

IBM

Related People

Mueller, H: AUTHOR [+3]

Abstract

The present method provides for the formation of buried subcollectors displaying a minimum of piping problems which cause leakage across subcollector boundaries, when the subcollectors are used in conventional planar bipolar integrated circuits.

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Forming Buried Subcollectors by Ion Implantation

The present method provides for the formation of buried subcollectors displaying a minimum of piping problems which cause leakage across subcollector boundaries, when the subcollectors are used in conventional planar bipolar integrated circuits.

In forming the subcollector by ion implantation, the present method follows conventional expedients in steps 1 and 2. On a P-silicon substrate 10, there is formed a silicon dioxide ion implantation barrier mask having thick regions 11 which will block the ions and thin regions 11', e.g., about 200 - 300 Angstroms thick in the regions which are to be ion implanted. Then, in step 2 the structure is bombarded with arsenic ions in the conventional manner to form N+ surface region 12. step is carried out to drive region 12 deeper into the substrate 10 without the removal of mask 11 - 11'. However, in accordance with the present method as shown in step 3, silicon dioxide mask 11 - 11' is removed before the reoxidation-drive-in step. Then, step 4, reoxidation and drive-in is carried out at a temperature in the order of 1100 degrees C for about one hour using conventional reoxidation and drive-in techniques.

This forms a structure shown in step 4 with arsenic doped region 12 being driven further into the substrate, and a new silicon dioxide layer 13 formed on the substrate 10. It should be noted that because thermal oxidation of the substrate is somewhat enhanced in the ion implant...