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Browse Prior Art Database

Lower Defect Densities in Implanted Arsenic Subcollector Devices

IP.com Disclosure Number: IPCOM000088847D
Original Publication Date: 1977-Aug-01
Included in the Prior Art Database: 2005-Mar-04
Document File: 2 page(s) / 36K

Publishing Venue

IBM

Related People

Beyer, KD: AUTHOR [+3]

Abstract

The described process does not introduce any defects after the completion of the arsenic implant subcollector process, Arsenic ions with an energy of 50 KeV and a dose of 10/16/ atoms/cm are implanted through a 250 Angstroms screening oxide (SiO(2)) layer 5 into the P- silicon in the SiO(2) subcollector mask 6 opening, according to Fig. 1. An arsenic implanted damage region 7 results. A partial SiO(2)-strip in a 40:1 buffered HF solution for 40 sec. or by a 30 sec. HF/H(2)O vapor etch over a solution consisting of 1 part 49% HF and 2 parts H(2)O follows the implantation. A 100 min. drive-in is done in a nonoxidizing ambient, such as argon or nitrogen.

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Lower Defect Densities in Implanted Arsenic Subcollector Devices

The described process does not introduce any defects after the completion of the arsenic implant subcollector process, Arsenic ions with an energy of 50 KeV and a dose of 10/16/ atoms/cm are implanted through a 250 Angstroms screening oxide (SiO(2)) layer 5 into the P- silicon in the SiO(2) subcollector mask 6 opening, according to Fig. 1. An arsenic implanted damage region 7 results. A partial SiO(2)-strip in a 40:1 buffered HF solution for 40 sec. or by a 30 sec. HF/H(2)O vapor etch over a solution consisting of 1 part 49% HF and 2 parts H(2)O follows the implantation. A 100 min. drive-in is done in a nonoxidizing ambient, such as argon or nitrogen.

After the drive-in, the thin SiO layer 5 is removed by a 30 sec. HF/H(2)O vapor etching over a solution consisting of 1 part 49% HF and 2 parts H(2)O. Following the removal of the thin SiO(2)-layer 5, a silicon etch, such as mixtures of HF and HNO(3), is applied in order to remove the shallow implantation damage of region 7. The silicon etching time is adjusted in such a way that approximately 1000 Angstroms of silicon is etched in order to minimize the sheet resistance decrease of the arsenic subcollector diffusion. This silicon etching step also eliminates the stacking faults formed during the initial oxidation in the subcollector window, and introduces a silicon step at the edge of the SiO(2) mask 6 window. The subcollector 8 is formed through the o...