US 12,232,324 B2
Method of forming oxide-nitride-oxide stack of non-volatile memory and integration to CMOS process flow
Michael Allen, Buda, TX (US); and Krishnaswamy Ramkumar, San Jose, CA (US)
Assigned to Infineon Technologies LLC, San Jose, CA (US)
Filed by Infineon Technologies LLC, San Jose, CA (US)
Filed on Sep. 27, 2022, as Appl. No. 17/954,141.
Prior Publication US 2024/0107771 A1, Mar. 28, 2024
Int. Cl. H10B 43/30 (2023.01); H01L 21/02 (2006.01)
CPC H10B 43/30 (2023.02) [H01L 21/02129 (2013.01); H01L 21/02219 (2013.01); H01L 21/02236 (2013.01)] 22 Claims
OG exemplary drawing
 
1. A method of fabrication of a semiconductor device, comprising:
dividing a substrate into first and second regions;
forming a customizable oxide-nitride-oxide (ONO) stack in the first region, comprising:
performing at least one of a first radical oxidation and a first oxide deposition process steps in an atomic layer deposition (ALD) tool to form a tunnel dielectric layer overlying the substrate;
performing a plurality of silicon nitride deposition process steps in the ALD tool to form a multi-layer charge trapping (CT) layer, comprising:
determining process parameters of a first silicon nitride deposition process step of the plurality of silicon nitride deposition process steps to form a first CT sub-layer;
modifying at least one of the process parameters;
performing a second silicon nitride deposition process step to form a second CT sub-layer overlying the first CT sub-layer; and
performing at least one of a second radical oxidation and a second oxide deposition process steps in the ALD tool to form a blocking dielectric layer overlying the multi-layer CT layer in the first region, wherein the multi-layer CT layer includes at least three CT sub-layers, and wherein the process parameters of the plurality of silicon nitride deposition process steps are modified such that a top CT sub-layer that is adjacent to the blocking dielectric layer is the most oxygen-lean and a bottom CT sub-layer that is adjacent to the tunnel dielectric layer is the most oxygen-rich in the multi-layer CT layer.