EE 2212

PROBLEM SET 3

S. G. Burns

Due: Monday, 15 February

Note 1: I strongly encourage you to study the Semiconductor supplement I posted SemiconductorDeviceProcessingSupplementTextSection2.11.pptx in preparing for Quiz 3 and to assist you with this problem set.

Note 2: Use Figure 2.8 on Text Page 55 for obtaining mobilities. Do not use the empirical “curve-fit” formulas next to Figure 2.8. By using graphs and curves, you do not have to perform any algebraic messy calculations using the polynomial curve fits.!!!

Note 3: Use the Solecon curves Solecon.JPG posted on the EE 2212 WEB page for resistivities, ρ.

Observe that the Solecon curves use log-log scales and Figure 2.8 Mobility.JPG use semi-log scales. If you are unfamiliar on how to read the log-log or semi-log scales on these types of graphs, ask.

Note 4: General material conductivity given by ConductivityRev1.jpeg

1. Text Problems 2.30 and 2.31

2. From an amalgamation of old quiz problems and using concepts in Text Problems 2.30 and 2.31. You are to evaluate the properties of a resistor fabricated from a rectangular solid piece of doped Si.

W = 0.5 mm, T = 100Å, and L = 10 mm. Use the Solecon resistivity curves and the text mobility curves. Assume n_i= 1.0 x 10¹⁰cm^-3 (refer to the table on the inside front cover although many references and graphs show this as n_i= 1.5 x 10¹⁰cm^-3) Units are important!

(a) Fill in the Table Assume the rectangular solid is donor doped Si doped with N_D= 3 x 10¹⁷cm^-3

PROPERTY	ANSWER
List two possible donor dopants
Majority Carrier Type and Density
Minority Carrier Type and Density
Resistivity
Mobility
Resistance between Terminals A and B

(a) Fill in the Table Assume the rectangular solid is now acceptor doped Si doped with N_A= 3 x 10¹⁷cm^-3

PROPERTY	ANSWER
List two possible acceptor dopants
Majority Carrier Type and Density
Minority Carrier Type and Density
Resistivity
Mobility
Resistance between Terminals A and B

3. Resistor Design and Analysis

(a) Estimate the mobility, μ, and the resistivity, ρ, if this resistor were fabricated from phosphorus-doped Si where N_D = 3 x 10¹⁷ cm^-3. Also compute the value of the resistance obtained between terminals C and D and A and B.. Use graphs.

(b) Estimate the mobility, μ, and the resistivity, ρ, if this resistor were fabricated from boron-doped Si where N_A = 3 x 10¹⁷ cm^-3. Also compute the value of the resistance obtained between terminals C and D and A and B.. Use graphs.

4. Refer to Table 2.3, page 44 in the text. Watch your units!

(a) Compute the wavelength for a photon emitted from GaAs, GaN, and InP and indicate their relationship to the wavelengths associated with the human visual optical spectrum.

(b) Suppose you had the design responsibility to bandgap engineer a semiconductor material to provide LASER optical emission for the applications listed below. Provide numerical values in eV for a material band gap energy to meet these applications.

i. DVD players or a high end game console using blue LASERS (i.e. SONY BLU-RAY^TM DVDs or HD Format DVDs)

ii. A CD player solid-state LASER operating in the near-infrared. Of course CDs are rapidly becoming obsolete.

iii. Green LASER pointer.

iv. Lowest loss optical fiber spectral window for contemporary optical fiber transmission lines. Use the graph below.