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Method to Form Frontside Substrate Contact

IP.com Disclosure Number: IPCOM000108129D
Original Publication Date: 1992-Apr-01
Included in the Prior Art Database: 2005-Mar-22
Document File: 2 page(s) / 49K

Publishing Venue

IBM

Related People

Mei, SN: AUTHOR [+3]

Abstract

A method to achieve a low resistance frontside contact to a P-/P+ substrate has been developed. This novel process describes a series of ion implant and oxidation anneal steps which results in a lower resistance path to the P+ substrate than previously used techniques. The process is described below via various illustrations. Referring to Fig. 1: . A P-/P+ substrate (about 5 mm P- epi) with 200 Ao SiO2 and 200 Ao Si3N4 layers; . Thick (5-6 mm) photoresist to form desired contact pattern; . 200 Ao silicon nitrite etched using RIE from developed pattern; . Boron I/I, 800 KeV, 1E15/cm2, (Rp ~ 1.5 mm). Referring to Fig. 2:. . Reoxidation of non-Si3N4 area to ~ 2000 Ao; . Remove 200 A"o silicon nitrite from remaining region; . Arsenic ion implant, 50 KeV, 1E16/cm2, (Rp ~ 300 Ao). Referring to Fig. 3: .

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Method to Form Frontside Substrate Contact

       A method to achieve a low resistance frontside contact to
a P-/P+ substrate has been developed.  This novel process describes a
series of ion implant and oxidation anneal steps which results in a
lower resistance path to the P+ substrate than previously used
techniques.  The process is described below via various
illustrations.
Referring to Fig. 1:
.   A P-/P+ substrate (about 5 mm P- epi) with 200 Ao SiO2 and 200
Ao Si3N4 layers;
.   Thick (5-6 mm) photoresist to form desired contact pattern;
.   200 Ao silicon nitrite etched using RIE from developed pattern;
.   Boron I/I, 800 KeV, 1E15/cm2, (Rp ~ 1.5 mm).
Referring to Fig. 2:.
.   Reoxidation of non-Si3N4 area to ~ 2000 Ao;
.   Remove 200 A"o silicon nitrite from remaining region;
.   Arsenic ion implant, 50 KeV, 1E16/cm2, (Rp ~ 300 Ao).
Referring to Fig. 3:
.   Subcollector drive-in process and N_epi deposition;
.   Link-up boron I/I, 100 KeV, 1E15/cm2 and R1 resistor boron I/I,
30 Kev, 3.3E14/cm2 .
Referring to Fig. 4:
.   SIMS profile of described process results in greater linkup of P+
substrate to frontside boron contact.  A lower contact resistivity (~
2KL mm2) has been achieved.
Referring to Fig. 5:
.   SIMS profile of standard process is shown which gives high
contact resistivity (~ 2KL mm2)