8/11/2019 ELEN90045_2014 Sem2_Assignment.pdf

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ELEN90045 2014 (Sem-2) Assignment,  20% (Total marks-60) 

1.  Oxygen diffuse through oxide layer according to Fick’s first law of diffusion 

  ( )  ⁄ . The rate of change of oxide thickness is given by ⁄ ⁄ . At the

Si-SiO2 interface, assume that the oxidation rate is proportional to the concentration of oxidizingspecies such that   (the symbols in the equations are defined in your lecture notes).

Derive the equations which describe the thickness of oxide on the wafer as a function of time.

Use the following boundary condition ( ) . - 6 

2. 

A <100> silicon wafer has 400 nm of oxide on its surface. How long will it take to grow an

additional 1 µm of oxide in wet oxygen at 1100oC? Use the silicon dioxide growth graph on the

SiO2 worked example page of your lecture notes (Semiconductor Processing). Compare graphical

and mathematical results. - 4

3. 

A phosphorus diffusion has a surface concentration of 5×1018/cm3, and the background

concentration of the p-type wafer is 1×1015

/cm3. The Dt product for the diffusion is 10

-8cm

2. - 6 

a. 

Find the junction depth for a Gaussian distribution

b.  Find the junction depth for an erfc profile

c. 

Draw a graph of the two profiles.

4. 

Boron is implanted with energy of 60 keV through a 0.25µm layer of silicon dioxide. The

implanted dose is 1×1014

/cm2. Using the projected range and straggle graphs of your lecture

notes. - 6

a. 

Find the boron concentration at the silicon-silicon dioxide interfaceb.  Find the dose in silicon.

c. 

Determine the junction depth if the background concentration is 3×1015

/cm3.

5.  Based on the following Paper-1, write two-page (A4) review summarising the key points of

the paper. - 10 

Paper-1:  H. Michael, and S. Hauch, “The future of integrated circuits: a survey of

nanoelectronics,” Proc. IEEE, vol. 98, Jan. 2010, pp. 11-38.

6. 

Based on the following Paper-2, answer following questions.

Paper-2: R. Garcia, A. W. Knoll and E. Riedo, “Advanced scanning probe lithography”

Nature Nanotechnology, Vol. 9 (2014) page-577.

(a) 

Write three advantages of SPL over conventional lithography. -3

(b)  Note the basic difference between thermal (t-SPL) and thermochemical (tc-SPL). -3

(c) 

Lists main parameters that control the local oxidation process in oxidation SPL (o-SPL). -5

(d) 

Based on Fig. 5 (Paper-2), describe the Ferritin deposition process. -6

(e) 

What is the main control parameter of molecular deposition in dip-pen SPL. -1 

7.  Write a short report (limit to 5-pages) on Melbourne Centre for Nanofabrication (MCN) tour.

- 10 ~0~