EE6312: Homework Assignment 1

For the homework assignments you will be using the TSMC 0.18u technology.

Before you start on your homework, download, print-out and fill out the following non-disclosure agreement with MOSIS.
NDA Form
Hand it in at the next lecture or put it in the TA's mailbox. No form - no hw grades!

The following are the different kinds of devices available in the technology:

1. 1.8V nominal Vt nMOS -- min L=180nm, min W=220nm
2. 1.8V nominal Vt pMOS -- min L=180nm, W=220nm
3. 1.8V Zero Vt native nMOS -- min L=500nm, min W=220nm
4. 1.8V medium Vt nMOS -- min L=300 nm, min W=220nm
5. 3.3V nominal Vt nMOS -- min L=350nm, min W=220nm
6. 3.3V nominal Vt pMOS -- min L=300nm, min W=220nm
7. 3.3V Zero Vt native nMOS -- min L=1.2um, min W=220nm
8. 3.3V medium Vt nMOS -- min L=600nm, min W=220nm

Each group uses one of the above devices. If your group number is N, select (N mod 8)+1 as the device to use! So if you are group 5, choose device 6, if you are group 8, choose device 1 etc.

Create a grid of devices sweeping W and L. Use minimum W, 3x min W, 9x min W and use min L, 3x min L, 9x min L. You have a 3x3 grid of nine devices.

CVN Students: Use the 1.8V nominal Vt device, and use min W, 3x min W, 9x min W for a length of 3x min L.

Plots and Estimations:

Now for each of the above devices plot the following:

1. log I_DS vs V_GS when V_DS = 1V for 1.8V devices, 2V for 3.3V devices.
2. I_DS vs V_GS when V_DS = 1V for 1.8V devices, 2V for 3.3V devices.
3. sqrt(I_DS) vs V_GS as above.
4. log I_DS vs V_DS for different V_GS. Step V_GS from 0 to Vdd in steps of 0.2V. Vdd is 1.8V or 3.3V depending on the device you are using.
5. I_DS vs V_DS as above.

Now for each length, plot Vt of the device as a function of width.

For each width, plot Vt of the device as a function of length.

Estimations: (For each device that you test)

1. Estimate alpha for each device. In strong inversion in the linear region I_DS is a function of V_GS, V_DS and alpha.
2. Estimate n - the subthreshold slope for each device. You will get this from the log I_DS vs V_GS curve. The slope is n*phi_t.
3. Estimate gamma - the body voltage coefficient. For this you will need to sweep V_SB of the device and see how the threshold voltage changes.
4. Estimate the early voltage V_A (Volts) and early voltage per unit length V_AL (Volts/um) from your I_DS vs V_DS curves.
5. Estimate I_Z: the characteristic current in moderate inversion.

References:

Notes:

You need to include the tsmc 0.18u library in your cds.lib if you don't see it when you run icfb for the first time. Add the following line to your cds.lib file:
INCLUDE /usr/tech/tsmc018/cdslib/tsmc018.lib
If you don't have a cds.lib file, create one in your home directory and add the line in it.

Models:
Use the following model file in spectre:
/usr/tech/tsmc018/tsmc018/mm018.scs

Device	Model name	Section
1.8V pMOS, nMOS regular devices	nch, pch	tt
3.3V pMOS, nMOS regular devices	nch3, pch3	tt_3v
1.8V zero Vt nMOS	nanch	tt_na
3.3V zero Vt nMOS	nanch3	tt_3vna
1.8V medium Vt nMOS	mench	tt_m
3.3V medium Vt nMOS	mench3	tt_3m

Submission: