def DriftDiffusionInitialSolution(device, region, circuit_contacts=None):
####
#### drift diffusion solution variables
###
CreateSolution(device, region, "Electrons")
CreateSolution(device, region, "Holes")
####
#### create initial guess from dc only solution
####
ds.set_node_values(device=device,
region=region,
name="Electrons",
init_from="IntrinsicElectrons")
ds.set_node_values(device=device,
region=region,
name="Holes",
init_from="IntrinsicHoles")
###
### Set up equations
###
CreateSiliconDriftDiffusion(device, region)
for i in ds.get_contact_list(device=device):
if circuit_contacts and i in circuit_contacts:
CreateSiliconDriftDiffusionAtContact(device, region, i, True)
else:
CreateSiliconDriftDiffusionAtContact(device, region, i)
def get_ds_status():
devices = ds.get_device_list()
for device in devices:
print("Device: " + device)
regions = ds.get_region_list(device=device)
for region in regions:
print("\tRegion :" + region)
params = ds.get_parameter_list(device=device, region=region)
for param in params:
val = ds.get_parameter(device=device,
region=region,
name=param)
print(f"\t\t{param} = {val}")
n_models = ds.get_node_model_list(device=device, region=region)
for node_model in n_models:
nmvals = ds.get_node_model_values(device=device,
region=region,
name=node_model)
print(f"\t\t Node Model '{node_model}' = {nmvals!s}")
e_models = ds.get_edge_model_list(device=device, region=region)
for edge_model in e_models:
emvals = ds.get_edge_model_values(device=device,
region=region,
name=edge_model)
print(f"\t\t Edge Model '{edge_model}' = {emvals!s}")
contacts = ds.get_contact_list(device=device)
for contact in contacts:
print("\tContact : " + contact)
c_eqs = ds.get_contact_equation_list(device=device,
contact=contact)
for ceq in c_eqs:
print("\t\tContact Equation : " + ceq)
def get_ds_status(short=True):
"""
Prints the status of the current devsim setup and all variables, solutions, node models and edge models
:return:
"""
for device in ds.get_device_list():
print("Device: " + device)
for region in ds.get_region_list(device=device):
print("\tRegion :" + region)
params = ds.get_parameter_list(device=device, region=region)
for param in params:
val = ds.get_parameter(device=device,
region=region,
name=param)
print(f"\t\t{param} = {val}")
for node_model in ds.get_node_model_list(device=device,
region=region):
nmvals = ds.get_node_model_values(device=device,
region=region,
name=node_model)
nmstr = ','.join([f'{val:.3g}' for val in nmvals])
print(f"\t\tNode Model '{node_model}' = {nmstr!s}")
e_models = ds.get_edge_model_list(device=device, region=region)
for edge_model in e_models:
emvals = ds.get_edge_model_values(device=device,
region=region,
name=edge_model)
emstr = ','.join([f'{val:.3g}' for val in emvals])
print(f"\t\tEdge Model '{edge_model}' = {emstr}")
for interface in ds.get_interface_list(device=device):
print("\tInterface: " + interface)
for imodel in ds.get_interface_model_list(device=device,
interface=interface):
intstr = ','.join([
f'{val:.3g}' for val in ds.get_interface_model_values(
device=device, interface=interface, name=imodel)
])
print(f"\t\tInterface Model: '{imodel}' = {intstr}")
for ieq in ds.get_interface_equation_list(device=device,
interface=interface):
# comm = ds.get_interface_equation_command(device=device, interface=interface, name=ieq)
print(f"\t\tInterface Equation: {ieq}")
contacts = ds.get_contact_list(device=device)
for contact in contacts:
print("\tContact : " + contact)
c_eqs = ds.get_contact_equation_list(device=device,
contact=contact)
for ceq in c_eqs:
print("\t\tContact Equation : " + ceq)
def get_voltage_current(device=None, contact=None, ece_name="ElectronContinuityEquation",
hce_name="HoleContinuityEquation"):
'''
Return voltage and current for the device
'''
if device is None:
device = ds.get_device_list()[0]
logger.warning(f"No device specified! Assuming '{device}'")
if contact is None:
contact = ds.get_contact_list(device)[0]
electron_current = ds.get_contact_current(device=device, contact=contact, equation=ece_name)
hole_current = ds.get_contact_current(device=device, contact=contact, equation=hce_name)
total_current = electron_current + hole_current
voltage = ds.get_parameter(device=device, name=f"{contact}_bias")
return voltage, total_current
def get_ds_equations():
devices = ds.get_device_list()
for device in devices:
print("Device: " + device)
regions = ds.get_region_list(device=device)
for region in regions:
print("\tRegion :" + region)
eqs = ds.get_equation_list(device=device, region=region)
print(f"\t\t{eqs!s}")
# params = ds.get_parameter_list(device=device, region=region)
for eq in eqs:
val = ds.get_equation_command(device=device,
region=region,
name=eq)
print(f"\t\t{eq} = {val}")
contacts = ds.get_contact_list(device=device)
for contact in contacts:
print("\tContact : " + contact)
c_eqs = ds.get_contact_equation_list(device=device,
contact=contact)
for ceq in c_eqs:
print("\t\tContact Equation : " + ceq)
####
volts = []
current = []
v = 0.0
while v < 0.51:
# plot_charge([region])
set_parameter(device=device, name=GetContactBiasName("bot"), value=v)
set_parameter(device=device, name=GetContactBiasName("top"), value=0.0)
print(v)
solve(type="dc",
absolute_error=1e6,
relative_error=1e-12,
maximum_iterations=300)
# PrintCurrents(device, "top")
# PrintCurrents(device, "bot")
for contact in ds.get_contact_list(device=device):
e_current = abs(
ds.get_contact_current(device=device,
contact=contact,
equation=ECE_NAME))
e_current += abs(
ds.get_contact_current(device=device,
contact=contact,
equation=HCE_NAME))
current.append(e_current)
volts.append(v)
v += 0.02
# plt.show()
plt.figure()
plt.semilogy(volts, current)
plt.figure()
def setup_drift_diffusion(self,
dielectric_const=11.9,
intrinsic_carriers=1E10,
work_function=4.05,
band_gap=1.124,
Ncond=3E19,
Nval=3E19,
mobility_n=1107,
mobility_p=424.6,
Nacceptors=0,
Ndonors=0):
"""
Sets up equations for a drift-diffusion style of dc current transport.
kwargs here are device-level parameters, imbuing all regions with these properties
If a specific region or material is to have a different set of parameters, they can be set through the
Region constructor.
:param dielectric_const:
:param intrinsic_carriers:
:param work_function:
:param band_gap:
:param Ncond:
:param Nval:
:param mobility_n:
:param mobility_p:
:param Nacceptors:
:param Ndonors:
:return:
"""
# Begin legacy copy-paste job
# Set silicon parameters
device = self.name
region = self.regions[0].name
eps_si = dielectric_const
n_i = 1E10
k = kb
mu_n = mobility_n
mu_p = mobility_p
set_parameter(device=device,
region=region,
name="Permittivity",
value=eps_si * eps_0)
set_parameter(device=device,
region=region,
name="ElectronCharge",
value=q)
set_parameter(device=device, region=region, name="n_i", value=n_i)
set_parameter(device=device, region=region, name="T", value=T)
set_parameter(device=device, region=region, name="kT", value=k * T)
set_parameter(device=device,
region=region,
name="V_t",
value=k * T / q)
set_parameter(device=device, region=region, name="mu_n", value=mu_n)
set_parameter(device=device, region=region, name="mu_p", value=mu_p)
# default SRH parameters
set_parameter(device=device, region=region, name="n1", value=n_i)
set_parameter(device=device, region=region, name="p1", value=n_i)
set_parameter(device=device, region=region, name="taun", value=1e-5)
set_parameter(device=device, region=region, name="taup", value=1e-5)
# CreateNodeModel 3 times
for name, value in [('Acceptors', "1.0e18*step(0.5e-5-x)"),
('Donors', "1.0e18*step(x-0.5e-5)"),
('NetDoping', "Donors-Acceptors")]:
result = node_model(device=device,
region=region,
name=name,
equation=value)
logger.debug(f"NODEMODEL {device} {region} {name} '{result}'")
print_node_values(device=device, region=region, name="NetDoping")
model_name = "Potential"
node_solution(name=model_name, device=device, region=region)
edge_from_node_model(node_model=model_name,
device=device,
region=region)
# Create silicon potentialOnly
if model_name not in get_node_model_list(device=device, region=region):
logger.debug("Creating Node Solution Potential")
node_solution(device=device, region=region, name=model_name)
edge_from_node_model(node_model=model_name,
device=device,
region=region)
# require NetDoping
for name, eq in (
("IntrinsicElectrons", "n_i*exp(Potential/V_t)"),
("IntrinsicHoles", "n_i^2/IntrinsicElectrons"),
("IntrinsicCharge",
"kahan3(IntrinsicHoles, -IntrinsicElectrons, NetDoping)"),
("PotentialIntrinsicCharge", "-ElectronCharge * IntrinsicCharge")):
node_model(device=device, region=region, name=name, equation=eq)
node_model(device=device,
region=region,
name=f"{name}:{model_name}",
equation=f"simplify(diff({eq},{model_name}))")
# CreateNodeModelDerivative(device, region, name, eq, model_name)
### TODO: Edge Average Model
for name, eq in (("ElectricField",
"(Potential@n0-Potential@n1)*EdgeInverseLength"),
("PotentialEdgeFlux",
"Permittivity * ElectricField")):
edge_model(device=device, region=region, name=name, equation=eq)
edge_model(device=device,
region=region,
name=f"{name}:{model_name}@n0",
equation=f"simplify(diff({eq}, {model_name}@n0))")
edge_model(device=device,
region=region,
name=f"{name}:{model_name}@n1",
equation=f"simplify(diff({eq}, {model_name}@n1))")
equation(device=device,
region=region,
name="PotentialEquation",
variable_name=model_name,
node_model="PotentialIntrinsicCharge",
edge_model="PotentialEdgeFlux",
variable_update="log_damp")
# Set up the contacts applying a bias
is_circuit = False
for contact_name in get_contact_list(device=device):
set_parameter(device=device,
name=f"{contact_name}_bias",
value=0.0)
# CreateSiliconPotentialOnlyContact(device, region, contact_name)
# Start
# Means of determining contact charge
# Same for all contacts
if not InNodeModelList(device, region, "contactcharge_node"):
create_node_model(device, region, "contactcharge_node",
"ElectronCharge*IntrinsicCharge")
#### TODO: This is the same as D-Field
if not InEdgeModelList(device, region, "contactcharge_edge"):
CreateEdgeModel(device, region, "contactcharge_edge",
"Permittivity*ElectricField")
create_edge_model_derivatives(device, region,
"contactcharge_edge",
"Permittivity*ElectricField",
"Potential")
# set_parameter(device=device, region=region, name=GetContactBiasName(contact), value=0.0)
contact_bias_name = f"{contact_name}_bias"
contact_model_name = f"{contact_name}nodemodel"
contact_model = f"Potential -{contact_bias_name} + ifelse(NetDoping > 0, -V_t*log({CELEC_MODEL!s}/n_i), V_t*log({CHOLE_MODEL!s}/n_i))"\
CreateContactNodeModel(device, contact_name, contact_model_name,
contact_model)
# Simplify it too complicated
CreateContactNodeModel(
device, contact_name, "{0}:{1}".format(contact_model_name,
"Potential"), "1")
if is_circuit:
CreateContactNodeModel(
device, contact_name,
"{0}:{1}".format(contact_model_name,
contact_bias_name), "-1")
if is_circuit:
contact_equation(device=device,
contact=contact_name,
name="PotentialEquation",
variable_name="Potential",
node_model=contact_model_name,
edge_model="",
node_charge_model="contactcharge_node",
edge_charge_model="contactcharge_edge",
node_current_model="",
edge_current_model="",
circuit_node=contact_bias_name)
else:
contact_equation(device=device,
contact=contact_name,
name="PotentialEquation",
variable_name="Potential",
node_model=contact_model_name,
edge_model="",
node_charge_model="contactcharge_node",
edge_charge_model="contactcharge_edge",
node_current_model="",
edge_current_model="")
# Biggie
# Initial DC solution
solve(type="dc",
absolute_error=1.0,
relative_error=1e-10,
maximum_iterations=30)
drift_diffusion_initial_solution(device, region)
solve(type="dc",
absolute_error=1e10,
relative_error=1e-10,
maximum_iterations=30)