Reference no: EM132704071

Question 1. Draw cross sectional diagrams of the major fabrication steps required for the fabrication of a p-MOSFET to be used as active load for an amplifier. Mention each major fabrication step with its specifications, e.g. masking oxide type and thickness, photolithography and its mask number, purpose of mask, pre-deposition or implantation, drive-in or implantation annealing, etc. How many masks are required for p-MOSFET fabrication? Final cross-sectional diagram must show the connections for p-MOSFET fabricated as active load.

Question 2. A p-Si wafer with uniform doping of 10¹⁵/cm³ undergoes the following process:
a. Deposit silicon dioxide of thickness 0.2μm
b. Define source and drain region 0.2μm wide, separated by gate regions or channel length of 0.1μm
c. Deposit gate oxide of 500A°, followed by deposition of n⁺⁺-Polysilicon of thickness 1,190A°
d. Photolithographically etch n⁺⁺-Polysilicon from source and drain region
e. Wafer goes through Phosphorus (P⁺) ion implantation at a dose of Q = 10¹¹/cm² followed by anneal at 1000°C for 15 minutes.
i. Select energy E of Phosphorous implant to put the peak of ion implant at the silicon-silicon dioxide in gate region
ii. Calculate the peak implant concentration Cp in source and drain after annealing, and the junction depth X_j of source and drain implant after annealing
iii. Calculate the dose escaping from field oxide (FOX) regions, i.e. FOX has thickness 0.2 gm of oxide + 500A° gate oxide + 1,190A° n⁺⁺Polysilicon
iv. Calculate the dose escaped Qp through gate in the channel region and calculate the change threshold voltage ΔVt of n-MOSFET due to escaping dose. Do Qp and ΔVt calculations for as-implanted case.
Given: cox = 3.9 and co= 8,85x10^-14F/cm, q = 1.6x10^-19C