EE2401 Project F19
EE 2401 Semiconductor Devices Project
Fall 2019
Introduction
You have been handed two devices, a diode and a MOSFET, that have unknown characteristics and
the identifying part numbers are not visible. In order to determine if the devices will work in an
upcoming project, you must determine the internal parameters for each device. Your subordinate has
already collected cu
ent-voltage characteristic data – your job is to determine from the data what the
desired parameters are.
Part I: p-n Junction Diode Characterization and Analysis
Cu
ent-voltage (I-V) characteristics of a p-n junction diode were measured under forward bias.
The recorded I-V data of the diode is available in the D2L module named “Semester Project”;
filename: Diode F19.xlsx. Complete the following tasks as described below and include in your
eport. Follow the report preparation instructions at the end of this document.
Task I: Analysis of Diode I-V Characteristics:
a) (9 pts) Plot the diode I-V curve (Graph l).
) (8 pts) Estimate the reverse saturation cu
ent (IS) following the procedure described below:
Plot ln(I) vs V (Graph 2). Then extrapolate the linear portion of the curve. The intercept of the
straight line with the y-axis is ln(lS) from which you can calculate IS.
c) (8 pts) Find the diode ideality factor (n) from the slope of the straight line in Graph 2 by using
the fact that the slope = 1/(n*Vt).
Task Il: Simulation:
a) (6 pts) Using the values of reverse saturation cu
ent and the ideality factor obtained in Task 1,
plot a simulated I-V curve (Graph 3) of the diode employing the diode cu
ent-voltage
equation.
Note: Plot both the experimental and the simulated I-V curves in Graph 3 for easy comparison.
) (4 pts) Do you notice any differences between the experimentally measured I-V characteristic
and this simulated I-V characteristic in Graph 3? If yes, then explain the possible reasons for
the differences.
Task Ill: Circuit Analysis:
(10 pts) Consider the series circuit comprising of the diode and a resistor of
10 Ω as shown in the right. The supply voltage, VS varies with time as
shown in Fig (a) on page 2.
Draw the cu
ent waveform in the space given in Fig (b).
Note: You must use the load line technique for this part. Do not use the
mathematical equations to find cu
ents. You must draw the necessary
load lines on Graph 1 [Show load lines and mark co
esponding operating
points. Find the cu
ents from the graph].
Part 2: n-MOSFET Characterization
Output characteristics of an n-channel MOSFET were recorded. The recorded I-V data of the
MOSFET is available in the D2L module named “Semester Project”; filename: n-MOSFET Data
F19.xlsx. Complete the following tasks as described below and include in your report. Follow
the report preparation instructions at the end of this document.
Task 1: Analysis of MOSFET I-V Characteristics
a) (6 pts) Plot the output characteristics (IDS vs VDS) of the n-MOSFET for VGS = 1V to VGS = 10V
on a single graph (Graph 4).
) (4 pts) Mark the channel pinch-off points (approximate) on each characteristic curve. Show
(mark) the saturation region of operation for the MOSFET on Graph 4
Note: All characteristic curves for ten different VGS values must be plotted on Graph 4.
Task II: Analysis of MOSFET Low-Voltage Characteristics
a) (5 pts) Plot the MOSFET's low-voltage output characteristics (IDS vs VDS) for VGS = 1V to VGS =
10V on another graph (Graph 5).
Note: This data is available on the 2nd excel page within the same excel file. The sheet is labeled
as 'Low Voltage Output Char'.
) (5 pts) Explain why the slope of the straight lines on Graph 5 increases with higher VGS?
Task III: Determination of MOSFET Parameters
a) (5 pts) Calculate the 'ON resistance' of the channel from Graph 5 for each Gate Voltage and list
the values in a table (Table l: RON vs VGS).
) (5 pts) Now, plot the ON Resistance vs Gate Voltage (Graph 6).
c) (2 pts) Find the drain saturation cu
ent, IDS(sat) co
esponding to each Gate Voltage (from Graph
4) and present the data in a table (Table 2: IDS(sat) vs VGS). Use the last IDS value listed for each
Gate Voltage
d) (2 pts) Calculate !?#$(???) and list it in Table 2 by adding a 3rd column.
e) (5 pts) Now, plot !?#$(???) vs VGS (Graph 7) and use a trendline on the plot to determine the
linear equation of the line (Hint: VT is the x-axis intercept of the line on Graph 7.)
f) (2 pts) Calculate the conduction parameter Kn of the MOSFET using the data. Find the value for
each gate voltage and then use the average in the next step
g) (2 pts) Calculate the transconductance (gm) in the saturation region for each Gate Voltage and
present the data in a table (Table 3: gm vs VGS).
h) (2 pts) Now, plot gm vs VGS (Graph 8).
Report Writing and Submission Instructions
• Write in a scientific/technical format. Use Times New Roman font (11 pt, single spacing) with a
margin of one inch on all sides.
• Use any professional graphical software to plot the Graphs such as Excel, Matlab, MathCad, etc.
• All graphs must be numbered, axes must be labeled with units and should be clearly visible.
• In the report, Do NOT include the measured I-V data in tables.
• Include sections and sub-sections as necessary; for e.g. Introduction/Objectives, Calculations,
Conclusions etc. Work co
esponding to each task must be marked clearly in the report.
• Tabulate your final parameters for each device and include them in your report:
o The diode: ideality factor and saturation cu
ent
o The MOSFET: threshold voltage and conduction parameter
• Assignment Due in the D2L submission dropbox by 11:59pm on Sunday, December 1, 2019.
Note: 10 points will be reserved for the overall presentation and report writing quality.
Grading: Total 100 points (15% of final grade)