Due: Wednesday April 27, ‘07 by 2:00 PM,the latest, via electronic submission to

You are required to fill in your answers in this word document and submit it along with your Mathematica file showing details/steps of your calculations

Your Name:

::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::

Prof. M.G. Guvench ELE 464 EXAM No.2 Take HomeApril 19, ‘07

( Closed Books/Notes, No Team-Work !)

::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::

Diffusion/Oxidation Data:

(hypothetical, for use in solving the following test problems only)

D @1000CD@1100C Solubility @1000Solubility @1100

Boron3.0E-15 cm2/s2.0E-14 cm2/s 2.0E20 cm-3 3.0E20 cm-3

Phosporus4.0E-15 cm2/s3.0E-14 cm2/s 8.0E20 cm-3 1.2 E21 cm-3

B@1000CB @1100C Phos @1000CPhos @1100C

Min.Oxide .008t (mins).018t (mins).015t(mins).020t(mins)

Thickness

()

Hole mobility (average): 250 cm2/V.s Electron mobility (average):1000 cm2/V.s

::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::

1.A Phosphorus predeposition at 1000 C gives a dopant dose Q of 1E14 cm-2. It is followed by a drive-in diffusion of one hour at 1100 C. Find:

a. the surface concentration after the predep,Answer 1a: ………… units?

b. the time it took for the predeposition,Answer 1b: ………… units?

c. the surface concentration after drive in, N(0), andAnswer 1c: ………… units?

d. the junction depth and the sheet resistance after all of these steps if the wafer were initially uniformly doped with phosphorous at 1E15 /cm3level and 0.4mm thick.

Answer 1d:………… units?Answer 1d: ………… units?

  1. the junction depth and the sheet resistance if the initial doping were boron instead of phosphorus in (d)?

Answer 1e:………… units?Answer 1e: ………… units?

2. A phosphorus doped 111 Silicon wafer (N=1.0E16 /cm3) is being ion implanted with boron at a dose of 1.0E14 /cm2. If the implantation results in a projected range of 90 nm and a straggle of 40 nm,

a. What is the maximum implant concentration in the implanted layer? Answer 2a: ………… units?

b. What is the resulting junction depth?Answer 2b: ………… units?

c. What is the sheet resistance of the implanted layer? Answer 2c: ………… units?

d. If a beam current of 100uA was swept over a square area of 40cm by 40cm how

long a time would the process specified above take?Answer 2d: ………… units?

e. What is junction depth, peak concentration and the sheet resistance if the

implantation is followed by a deep drive-in of 1 hour @ 1100 C.

Answer 2e: ………… units? Answer 2e: ………… units? Answer 2e: ………… units?

3. An N-type doped wafer (1E16 /cm3) and 1100 C 1Hr Boron diffusion is being used to

make silicon P+N diodes.

a. What is the junction depth?Answer 3a: ………… units?

b. What is the oxide thickness needed to do an effective mask?

Answer 3b: ………… units?

c. If the oxide is supposed to be grown at 1050 C dry, calculate the time required for oxidation

Answer 3c: ………… units?

  1. a. A 20X20 array of cavities (inkjet nozzles) with 10X10 um square openings is to be etched through a 500 um thick <100> Silicon wafer using anisotropic wet etching. What is the closest center to center spacing of the 10 um cavity openings? What is the area of the array?

Answer 4a:………… units?Answer 4a: ………… units?

b. Draw the cross section and top view of such an inkjet nozzle array, indicating distances and angles. (Attach the drawings to this document either drawn in Microsoft or scanned/screen captured image from another application.)