(a) The gate oxide for a CMOS process on 100 silicon is to have a thickness of 10 nm (100A) Calculate the time required to grow this oxide at 850 o C in wet oxygen Repeat the work for 1000 o C Do either of these possible processes seem to be under control (elaborate) t X 0 2 B X o (B A) t , A 2D k s , B 2DN 0 M, and t X i 2 B X i (B A), X i is the initial thickness of oxide on the wafer, t represents the time which would have been required to grow the initial oxide Usually, a thin native oxide layer (10 to 20 A is always present on silicon due to atmospheric oxidation D is the diffusion coefficient and N is the particle concentration k s is called the rate constant for the reaction at the Si SiO 2 interface, M is the number of molecules of the oxidizing species that are incorporated into a unit volume Boundary condition is X o (t 0) X i (b) A dry wet dry oxidation cycle of 30 minutes 120 minutes 30 minutes is performed at 1100 o C What is the final oxide thickness for a 100 silicon wafer What is the final oxide thickness for a 111 silicon wafer in problem two, part a, please take the gate oxide to be 100nm as some of you suggested, since the graphs will be more convenient to deal with You may make the problem also easier on yourself by saying the wafer will be cleaned through chemical mechanical polish to remove the native oxide and it will be kept in a clean controlled environment

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(a) The gate oxide for a CMOS process on <100> silicon is to have a thickness of 10 nm (100A). Calculate the time required to

(a) The gate oxide for a CMOS process on <100> silicon is to have a thickness of 10 nm (100A). Calculate the time required to grow this oxide at 850^oC in wet oxygen. Repeat the work for 1000^oC. Do either of these possible processes seem to be under control? (elaborate).

{t = {X₀² / B + X_o / (B/A) - t}, A = 2D/k_s, B = 2DN₀/ M, and t = X_i² / B + X_i / (B/A), X_i is the initial thickness of oxide on the wafer, t represents the time which would have been required to grow the initial oxide. Usually, a thin native oxide layer (10 to 20 A is always present on silicon due to atmospheric oxidation. D is the diffusion coefficient and N is the particle concentration. k_s is called the rate constant for the reaction at the Si-SiO₂ interface, M is the number of molecules of the oxidizing species that are incorporated into a unit volume. Boundary condition is X_o (t = 0) = X_i.}

(b) A dry-wet-dry oxidation cycle of 30 minutes/120 minutes/30 minutes is performed at 1100^oC. What is the final oxide thickness for a <100> silicon wafer? What is the final oxide thickness for a <111> silicon wafer?

in problem two, part a, please take the gate oxide to be 100nm as some of you suggested, since the graphs will be more convenient to deal with. You may make the problem also easier on yourself by saying the wafer will be cleaned through chemical/mechanical polish to remove the native oxide and it will be kept in a clean controlled environment.