• Lab 1 : 16th Jan
  • Asgn-1
    • Short Channel Device
    • Long Channel Device
  • Sentaurus TCAD
• Lab 2 : 2nd Feb
  • Doping and impurity
  • Assignment
• Lab 3 : missed (Duty Leave)
• Lab 4 : 16th Feb
  • Code
  • Electrode section
    • Physics section
  • Creating parameter files for materials
• Lab 5 : 23rd Feb
• Lab 6 : 8th March
• Lab 7 : 15th March Create pMOS
  • set contacts
  • To create MESH
• Lab 8 : 22rd March Missed
• Lab 9 : 5th April Missed
• Lab 10 : 12th April

Lab 1 : 16th Jan

username : root
password : ROOT100

Structure of mosfet
Gate control is only in 1 direction
MOS region
How to manufacture MOSFET

Mode of operation

1. Accumulation
2. Depletion
3. Inversion

For FINFET, gate control is in all 3 directions

Asgn-1

Three ports of nMOS and pMOS
Band diagram for the same

Why do we apply gate voltage => To create channel
Drain voltage => To allow flow of electrons

Short Channel Device

Channel length < 180nm
Effects like Channel length modulation, dibble and charge sharing (threshold voltage lowering) are observed.

Long Channel Device

Channel length > 180nm

Sentaurus TCAD

Technology Computer Aided Design

How to open sentaurus

Navigating the folders
home => desktop => tcad_lab => your_folder => open terminal

In the terminal;
csh
source cshrc_new
swb/sde (depending on mode you like to enter)

Process to be followed

1. SDE
   Structure Editor
   Create device

2. S Device
   Apply physics and to change properties
   Apply model to accurately simulate
   Ex : mobility of electrons depends on thickness of device and gate voltage

3. S Visual
   View results of the simulation, in a PDF file format

Lab 2 : 2nd Feb

Open sde (from terminal)
Create 2-D mosfet

Difference between mos-capacitor and mos-fet
Capacitor : between two plates

Germanium Device gets heated easily, hence not used widely.
Electron-hole mobility is greater in germanium.

Doping and impurity

Intrinsic doping : pure semiconductor material
Extrinsic doping : some impurity is added

n-type impurity

1. Phosphorus
2. Arsenic

p-type impurity

1. Boron
2. Aluminium

Region name	Material	x-dimension	y-dimension	remarks
substrate	silicon	0 to 0.09µm	0 to 0.07µm	p-type silicon substrate
source	silicon	0 to 0.030µm	0 to 0.025µm	a
drain	a	0.060 to 0.090 µm	0 to 0.025µm	a
oxide-channel	silicon oxide	0.03 to 0.06µm	0.06 to -0.002µm	a
gate-contact	tin	0.03 to 0.06µm	-0.002 to -0.004µm	a
source-contact	tin	0 to 0.02µm	0 to -0.002µm	a
drain-contact	tin	0.07 to 0.09µm	0 to -0.002µm	a
body-contact	tin	0 to 0.09µm	0.070 to 0.072µm	a

To avoid short circuiting, other contacts should be of smaller dimension.

Assignment

Differ bulk cmos technology and SOI cmos technology.

SOI : Silicon on Insulator
SOP : Silicon on Spire

Lab 3 : missed (Duty Leave)

Lab 4 : 16th Feb

Apply voltage on device and visualize results

Mobility
Temperature
Electric field
Scholkey recombination model

Code

shared
mesh.tdr

cmd file
log file : stores run time, meshes created

1. Add input file into grid file
2. Add devices

Grid file : file jiski characteristic dekhni hai
common.parameter file : Notes which material is used and its properties
At 300K, Silicon BandGap 1.1eV

$$E_g=E_o-3.6\ast {10}^{-}4\ast T$$

Contour plot
Observed after the experiments

Systemic diagram
dash.plot file
IDVG (IV curve for Drain Current, GateVoltage)
log file will also be generated for each run, storing difference in results

Electrode section

Metal Contacts,

Physics section

apply physics to the complete device

Relation between mobility and electric field

$$\mu =V_d/E$$

At low gate voltage, Vertical Electric Field dominates
At high gate voltage, Horizontal Electric Field dominates

Model

1. DopingDependece
2. Philips Unified Mobility Model PhuMob

Plot section
self explanatory, to observe variables

How to find saturation
Gradient stops changing, check by approximating

Solve section
Apply voltage

Creating parameter files for materials

1. Silicon
2. TiN
3. SiO2

csh
source schrc_new
sdevice -P:Silicon

rename model.par to Silicon.par

Create a common.par file for the common parameters. Copy a already created file and paste it in the same directory; rename this file and remove all contents to generate a new file.
Rename this file to common.par
Insert the materials using

Material = "Silicon"{Insert = "Silicon.par"}
Material = "SiO2"{Insert = "SiO2.par"}
Material = "TiN"{Insert = "TiN.par"}

Lab 5 : 23rd Feb

Refine Specification
RefEvalWin_1
select Define Ref/Eval window checkbox

	x axis	y axis	value
first	0	0
second	0.03	0.025

Under refinement definination section, change the name to source

	x axis	y axis
max element	0.005	0.005
min element	0.004	0.004

Click on build mesh, to get s-visual

Lab 6 : 8th March

Write all formula's you know on a sheet of paper, lab ended in 40mins

Lab 7 : 15th March Create pMOS

Right click, open terminal in roll-folder itself

Create pMOS, using the dimensions at following table

After creating these, dope the areas by clicking on "Constant Profile Placement"

1. Source, Drain Boron 2e17
2. Substrate Phosphorus 1e16

set contacts

All 4 neeed to be set
After adding all contacts to "contact set"

From dropdown, select the contact you want, right click on the diagram on the contact and under "Contacts" (in header toolbox) set contact
Click on activate.

To create MESH

define rel/eval window => rectangle
x 0 to 0.09
y -0.004 to 0.072

Meshing was unsuccesful, no grid file was generated
Tried changing mesh size as well, increase and decreased mesh size to observe if the total computation load leads to a failure in creation of mesh.

Lab 8 : 22rd March Missed

Lab 9 : 5th April Missed

Lab 10 : 12th April

drive link for all
Download as zip, extract and simply plot the first file

X axis
Y axis