In week 9 studio, you worked on CVD of silicon nitride (Sigma_3N_4) thin films f

Question

In week 9 studio, you worked on CVD of silicon nitride (Sigma_3N_4) thin films from a gas feed of dichlorosilane (SiCl_2H_2 or DCS) and ammonia (NH_3). The process grows film on both sides of a 300 mm wafer and there are 200 wafers processed per batch. Please perform the following analysis on the process. A. Write a balanced chemical equation for the reaction between dichlorosilane and ammonia gas that forms products of silicon nitride, hydrogen chloride gas, and hydrogen gas. B. If 1,000 A of silicon nitride film is required i. How many moles of dichlorosilane are needed? ii. How many cm^3 of ammonia gas at STP (0 degree C and 1 atm) is this? iii. How many moles of ammonia gas are needed? iv. How many cm^3 of ammonia gas at STP (0 degree C and 1 atm) is this? C. As the first reaction takes place, a second side-reaction begins immediately between the hydrogen chloride gas and ammonia gas. In this second reaction, ammonium chloride is produced. In other words, some of the ammonia gas in your balanced chemical equation determined in part A above gets consumed before forming the silicon nitride that you want. We will have to compensate for this. a. Write a balanced chemical equation for this secondary reaction between all of the hydrogen chloride gas produced from the first reaction and any additional ammonia gas that is needed. b. If all of the hydrochloric acid produced from the first reaction also reacts with ammonia gas, how many additional moles of ammonia gas will be required to still produce the 1,000 A film of silicon nitride? D. Combine the two reactions above to make a net balanced chemical reaction that accounts for the fact that the HCI produced in the first reaction combines with ammonia as described in the second reaction. E. If 100 sccm of dichlorosilane and 800 sccm of ammonia gas flow into the furnace at the same time, a. Which reactant runs out first? Is this desired? b. What is the thickest uniform film of silicon nitride that can be produced in 50 min?

Explanation / Answer

According to chegg policy if a question has nore than 4 subparts Then answer will be given for 1st part only

A. 3 SiH2Cl2 +4NH3- Si3N4+6HCl+6H2

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