nextnano³ - Tutorial

next generation 3D nano device simulator

1D Tutorial

HEMT structure (High Electron Mobility Transistor)

Authors: Stefan Birner

-> HEMT_1D_nn3.in / *_nnp.in - input file for the nextnano³ and nextnano++ software (1D simulation)
-> HEMT_2D_nn3.in
-> HEMT_3D_nn3.in

These input files are included in the latest version.

HEMT structure

• This input file simulates a HEMT structure: HEMT_1D_nn3.in
• It consists of:
  
  at    10 nm: Schottky barrier of 0.2 eV
  10 - 20 nm: In_0.532Ga_0.468As
  20 - 45 nm: Al_0.477In_0.523As
  45 - 95 nm: In_0.532Ga_0.468As
  95 - ... nm: Al_0.477In_0.523As
  The structure is grown on InP. There is no strain as everything is lattice matched. (Nevertheless, we still calculate the strain.)
  
  
   
• Now we add at x = 35 nm a silicon delta doping of 4.5 * 10¹² cm^-2 which leads to band bending.
  Instead of choosing a delta doping we specify a constant doping of 1.5 * 10²⁰ cm^-3 that extends over 0.3 nm.
  (1.5 * 10²⁰ cm^-3 * 3 * 10^-8 cm = 4.5 * 10¹² cm^-2)
  
  $doping-function
 ...
$end_doping-function

$impurity-parameters
 ...
$end_impurity-parameters

We obtain two eigenstates and their corresponding wave functions inside the HEMT channel which leads
  to a two-dimensional electron gas (2DEG). The electron density is plotted in blue.

• In the file densities/int_el_dens1D.dat we can find the integrated density in each region cluster.
  The total integrated density (from 10 nm to 100 nm) which can be measured experimentally is thus
  2.19 * 10¹² cm^-2 in agreement with the experiment. Most of the density is located between 45 nm and 95 nm, namely 2.05 * 10¹² cm^-2.

2D/3D simulations

-> HEMT_2D_nn3.in
-> HEMT_3D_nn3.in

Input files for the same HEMT structure as in 1D, but this time for a 2D and 3D simulation are also available.
==> 2D: rectangle of dimension 250 nm x 10 nm
==> 3D: cuboid     of dimension 250 nm x 10 nm x 10 nm