IV/CV measurements for silicon sensors.

On Windows download a pre-built executable from the release section and run it.

Install using pip in a virtual environment.

pip install https://github.com/hephy-dd/diode-measurement/archive/refs/tags/0.25.0.tar.gz

Building a Windows executable using PyInstaller.

# Create build environment
python3 -m venv build_env
. build_env/Scripts/activate

# Install dependencies
pip install --upgrade pip
pip install -e .
pip install -r .pyinstaller/requirements.txt

# Build executable
pyinstaller ./.pyinstaller/windows_app.spec

An executable will be created in dist/diode-measurement-{version}.exe

Source Meter Units

• Keithley 237
• Keithley 2410
• Keithley 2470
• Keithley 2657A

Electro Meter

• Keithley 6514
• Keithley 6517B

LCR Meter

• Agilent 4284A
• Keithley 595
• Keithley 4215-CVU
• Keysight E4980A

DMM (Temperature)

• Keithley 2700

TCU (Temperature Control Unit)

• ERS AC3 Fusion (Thermal Chuck)

Switching Matrix

• HEPHY BrandBox (HV Switch)
• Keithley 707B
• Keithley 708B

To interface instruments using a GPIB interface the NI-VISA drivers need to be installed. Interfacing instruments using TCPIP, USB or Serial port is supported out of the box by using PyVISA-py, pyusb and pyserial.

The instrument resource name inputs accept follwing formats:

The used plain text format consists of a header containing meta data in key and value pairs and one or more CSV data tables with headers using \t separators.

<key>: <value>
...
<<series>[<unit>]\t...>
<<value>\t...>
...

IV measurement data consist of up to two CSV tables with the second (optional) table containing continuous measurement data.

sample: Unnamed
measurement_type: iv
voltage_begin[V]: +5.000E+00
voltage_end[V]: -1.000E+01
voltage_step[V]: +1.000E+00
waiting_time[s]: +1.000E-01
current_compliance[A]: +1.000E-06

timestamp[s]	voltage[V]	v_smu[V]	i_smu[A]	i_elm[A]	i_elm2[A]	temperature[degC]
1629455368.29	+5.000E+00	+5.038E+00	+4.261E-08	+3.740E-08	+NAN	+NAN
1629455369.71	+4.000E+00	+4.065E+00	+7.708E-08	+9.495E-08	+NAN	+NAN
1629455370.49	+3.000E+00	+3.007E+00	+3.460E-08	+6.264E-08	+NAN	+NAN
...          	...       	...       	...       	...       	...       	...

timestamp[s]	voltage[V]	v_smu[V]	i_smu[A]	i_elm[A]	i_elm2[A]	temperature[degC]
1629455385.69	+3.000E+00	+3.046E+00	+3.996E-04	+7.137E-08	+NAN	+NAN
1629455387.65	+3.000E+00	+3.034E+00	+7.353E-04	+3.079E-08	+NAN	+NAN
1629455389.56	+3.000E+00	+3.021E+00	+9.081E-04	+1.266E-08	+NAN	+NAN
...          	...       	...       	...       	...       	...       	...

IV bias measurement data consist of up to two CSV tables with the second (optional) table containing continuous bias measurement data.

sample: Unnamed
measurement_type: iv_bias
bias_voltage[V]: +1.000E+01
voltage_begin[V]: +5.000E+00
voltage_end[V]: -1.000E+01
voltage_step[V]: +1.000E+00
waiting_time[s]: +1.000E-01
current_compliance[A]: +1.000E-06

timestamp[s]	voltage[V]	v_smu[V]	i_smu[A]	v_smu2[V]	i_smu2[A]	i_elm[A]	i_elm2[A]	temperature[degC]
1629455368.29	+5.000E+00	+5.038E+00	+4.261E-08	+1.063E+01	+3.723E-08	+3.740E-08	+NAN	+NAN
1629455369.71	+4.000E+00	+4.065E+00	+7.708E-08	+1.051E+01	+6.513E-08	+9.495E-08	+NAN	+NAN
1629455370.49	+3.000E+00	+3.007E+00	+3.460E-08	+1.058E+01	+2.410E-08	+6.264E-08	+NAN	+NAN
...          	...       	...       	...       	...       	...       	...       	...       	...

timestamp[s]	voltage[V]	v_smu[V]	i_smu[A]	v_smu2[V]	i_smu2[A]	i_elm[A]	i_elm2[A]	temperature[degC]
1629455385.69	+3.000E+00	+3.046E+00	+3.996E-08	+1.063E+01	+2.657E-08	+7.137E-08	+NAN	+NAN
1629455387.65	+3.000E+00	+3.034E+00	+7.353E-08	+1.063E+01	+6.154E-08	+3.079E-08	+NAN	+NAN
1629455389.56	+3.000E+00	+3.021E+00	+9.081E-08	+1.063E+01	+8.426E-08	+1.266E-08	+NAN	+NAN
...          	...       	...       	...       	...       	...       	...       	...       	...

CV measurement data consist of a single CSV table containing the measurement data.

sample: Unnamed
measurement_type: cv
voltage_begin[V]: +5.000E+00
voltage_end[V]: -1.000E+01
voltage_step[V]: +1.000E+00
waiting_time[s]: +1.000E-01
current_compliance[A]: +1.000E-08

timestamp[s]	voltage[V]	v_smu[V]	i_smu[A]	c_lcr[F]	c2_lcr[F]	r_lcr[Ohm]	temperature[degC]
1629455368.29	+5.000E+00	+5.065E+00	+4.261E-08	+3.740E-05	7.149E+08	3.459932E-01	+NAN
1629455369.71	+4.000E+00	+4.037E+00	+7.708E-08	+9.495E-05	1.109E+08	3.015286E-01	+NAN
1629455370.49	+3.000E+00	+3.043E+00	+3.460E-08	+6.264E-05	2.549E+08	2.482018E-01	+NAN
...          	...       	...       	...       	...      	...      	...

The application provides an JSON-RPC (remote procedure call) version 2.0 interface using a TCP server.

Start notification starts a new measurement.

{"jsonrpc": "2.0", "method": "start"}

Optional parameters are:

• continuous (Boolean)
• auto_reconnect (Boolean)
• measurement_type (one of iv, iv_bias, cv_diode, cv_mos)
• measurement_instruments (list of smu, smu2, elm, elm2, lcr, dmm, tcu, switch)
• begin_voltage (Volt)
• end_voltage (Volt)
• step_voltage (Volt),
• waiting_time (seconds)
• compliance (Ampere)
• waiting_time_continuous (seconds).

Note: specified values are applied to the user interface before starting a measurement.

{
  "jsonrpc": "2.0",
  "method": "start",
  "params": {
    "end_voltage": -100.0,
    "step_voltage": 10.0,
    "waiting_time": 1.0
  }
}

Stop notification stops an active measurement.

{"jsonrpc": "2.0", "method": "stop"}

Change voltage notification applies only during continuous It measurement.

Required parameters are:

• end_voltage (Volt)

Optional parameters are:

• step_voltage (Volt, default is 1.0)
• waiting_time (seconds, default is 1.0)

{
  "jsonrpc": "2.0",
  "method": "change_voltage",
  "params": {
    "end_voltage": 100.0,
    "step_voltage": 10.0,
    "waiting_time": 0.25
  }
}

Request an application state snapshot.

{"jsonrpc": "2.0", "method": "state", "id": 0}

This returns application state parameters.

{
  "jsonrpc": "2.0",
  "result": {
    "state": "ramping",
    "measurement_type": "iv",
    "sample": "VPX1",
    "source_voltage": 24.0,
    "smu_voltage": 24.026,
    "smu_current": 0.0025,
    "smu2_voltage": null,
    "smu2_current": null,
    "elm_current": 0.0021,
    "elm2_current": null,
    "lcr_capacity": null,
    "temperature": 24.031
  },
  "id": 0
}

Get current instrument options using method instrument.get.

Required parameter is:

• instrument (one of smu, smu2, elm, elm2, lcr, dmm, tcu, switch)

{
  "jsonrpc": "2.0",
  "method": "instrument.get",
  "params": {
    "instrument": "smu"
  },
  "id": 1
}

This returns the current model's instrument options.

{
  "jsonrpc": "2.0",
  "result": {
    "instrument": "smu",
    "model": "K2410",
    "options": {
      "filter.enable": false,
      "filter.count": 10,
      "filter.mode": "REP",
      "nplc": 1.0,
      "route.terminals": "REAR",
      "system.breakdown.protection": false,
    }
  },
  "id": 1
}

Note: option keys might change in future releases.

Update current instrument options using method instrument.update.

Required parameters are:

• instrument (one of smu, smu2, elm, elm2, lcr, dmm, tcu, switch)
• options (specific to selected instrument model)

{
  "jsonrpc": "2.0",
  "method": "instrument.update",
  "params": {
    "instrument": "smu",
    "options" : {
      "filter.enable": true,
      "filter.count": 25,
    }
  },
  "id": 2
}

This returns the current model's updated instrument options.

{
  "jsonrpc": "2.0",
  "result": {
    "instrument": "smu",
    "model": "K2410",
    "options": {
      "filter.enable": true,
      "filter.count": 25,
      "filter.mode": "REP",
      "nplc": 1.0,
      "route.terminals": "REAR",
      "system.breakdown.protection": false,
    }
  },
  "id": 2
}

Note: option keys might change in future releases.

Following states are exposed by the state snapshot:

• idle
• configure
• ramping
• continuous
• stopping

Example using netcat to start a new measurement and set a target end voltage:

echo '{"jsonrpc": "2.0", "method": "start", "params": {"end_voltage": 100.0}}' | nc localhost 4000

Example using Python to query the application state from the TCP server:

import json
import socket

with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as sock:
    sock.connect(("localhost", 4000))

    request = {
        "jsonrpc": "2.0",
        "method": "state",
        "id": None,
    }

    sock.sendall(json.dumps(request).encode("utf-8"))
    print(sock.recv(4096).decode("utf-8"))

Example using the DiodeMeasurementClient:

from rpc_client import DiodeMeasurementClient

client = DiodeMeasurementClient("localhost", 4000)

client.start(measurement_type="iv", end_voltage=100.0)

while client.current_state() != "idle":
    print(client.state())
    time.sleep(1)

See scripts for a reference client implementation and example scripts demonstrating how to use it.