2. INTRODUCTION
• A semiconductor junction consisting of multi-layered
thin pn-junctions, so-called SUPER-JUNCTION, has
been developed to overcome the limitation of the
conventional pn-junction. In this junction, positive
charges of donor in n-type semiconductor layers and
negative charges of acceptor in p-type semiconductors
layers appear, after a reverse voltage is applied to the
junction. The average charge density of them is
controlled to be very low as a whole. As a result, the
breakdown voltage is increased.
• In this project, our objective is to observe the different
structure of super-junction and simulate the structure to
enhance its performance. Here, we have simulated the
silicon based super-junction structure and observed the
resulting critical electric field.
3. WHAT IS SUPER-JUNCTION?
• Super-junction devices are designed to
break the “silicon limit”. The difference
between conventional device structure and
super-junction device structure is the drift
region design.
• It’s easily noted from fig.(a) that
conventional drift region composes of one
type epi-layer, either n or p, while the super-
junction drift region is made up of two types
oppositely doped, alternatively stacked epi-
layer. Fig.(b) shows an interdigitated p-n
column structure, which is most commonly
used. Other structure are also possible.
4. Experimental ideas from previous research:
We made the structure of Horizontal Super-junction Structure as per the super-
junction theory presented by Hidetoshi Ishida in his paper named “GaN-based
Natural Super-junction diodes with multichannel Structures”.
5. EXPERIMENT
• We keep the dimension of the whole structure as 2 x 1 µm2.
• For vertical Super-junction we took every n and p layer equal to each other and took the dimension as 1
x 0.4 µm2.
• For horizontal Super-junction we again kept the dimensions of both n and p-layer equal to each other
and took the dimension as 2 x 0.4 µm2.
• After making the base structure we finally add a thin ohmic contact both named as cathode and anode,
from there we are going to supply our reverse bias voltage.
• Now, it’s time for adding doping profile to the structure. For that we choose 1x1016 cm-3 of phosphorus
dopant for n-layer and 1x1016 cm-3 of boron dopant for p-type layer. For ohmic contacts we keep the
1x1018 cm-3 phosphorus doping concentration for cathode region and 1x1018 cm-3 boron doping
concentration for anode region, making the cathode region highly doped n-type region and anode a
highly doped p-type region.
• After adding constant profile concentration, it’s time to make the meshing for the simulation and
calculation part.
6. Horizontal Si Super-Junction Structure
(with doping concentration)
Vertical Si Super-Junction Structure
(with doping concentration)
7. Electric Field Profile: The Electric field pattern along with the graph plot is shown
below. The Critical EF found here is 0.45MV/cm.
(a) Electric-field pattern (b) scale (c) Electric-field plot
OBSERVATION (For Vertical Super-Junction Model)
8. OBSERVATION (For Horizontal Super-Junction Model)
Electric Field Profile: The Electric field pattern along with the graph plot is shown
below. The Critical EF found here is 0.24MV/cm.
(a) Electric-field pattern (b) scale (c) Electric-field plot
9. OBSERVATION (For conventional Si PiN junction Model)
Electric Field Profile: The Electric field pattern along with the graph plot is shown
below. The Critical EF found here is 0.4 MV/cm.
(a) Electric-field pattern (b) Scale
n+
n drift region
p+
(c) Electric-field plot
