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CHAPTER 5:
Advanced Operation
Model CRX-6.5K Probe Station
4. Turn all heaters off, and set all temperature setpoints to zero.
If the sample is already in place, proceed with temperature operation. If the
system is to be opened for sample exchange, close the vacuum isolation valve, turn off
and properly vent the turbo pumping system, and follow steps 4 to 6 of section 4.4.4.
5.2.1.2 Maintaining the Sample at Room Temperature While Cooling the Probe Station
The following procedure is a simple but effective way to minimize the condensation
on the sample. This is accomplished by cooling the radiation shield stage first so that
the majority of residual gas is attracted to it and not the sample.
Follow this procedure to reduce condensation on the sample:
1. Evacuate the chamber as described in section 4.4.2 or perform a heated cycle
purge as described in section 5.2.1.1.
2. Control the sample stage at 290 K using control settings in section 4.5.5
(Output 1 on the Model 336 temperature controller).
3. Cool the refrigerator by following the instructions in section 4.5.2. The tempera-
ture controller will keep the sample stage warm while the remainder of the probe
station cools to base temperature. At this point, any residual gas in the chamber
will condense on the radiation shield stage.
4. When the radiation shield stage is cooled to less than 70 K, turn off the sample
stage heater by pressing
ALL OFF
on the Model 336 temperature controller.
5. Allow the sample stage to cool to base temperature.
6. Operate the probe station normally.
5.2.2 High Temperature
Sample Stage
Operation
The Model CRX-6.5K probe station can be operated from 20 K to 675 K using the high
temperature (HT) sample stage option. The HT sample stage is a coaxially isolated
stage that is designed for 51 mm (2 in) diameter wafers. The HT stage option installa-
tion and removal from the Model CRX-6.5K probe station is similar to the sample
holder installation and removal. The HT sample stage has a platinum sensor embed-
ded in the top sample plate that is calibrated from 6 K up to 675 K for rated tempera-
ture operation in the Model CRX-6.5K. The HT sample stage has two 50 W heaters
(100 W total) that are arranged in parallel; the combined parallel heater resistance is
25
)
. Electrical connection to the coaxial stage may be made through the standard
CRX-6.5K FT-BNC or FT-triaxial option.
Prior to June 1, 2013, the Model CRX-6.5K refrigerator needed to be configured at the fac-
tory with the electrical wiring for operating the HT sample stage. After that date, all
Model CRX-6.5K refrigerators have the internal wiring to support the HT stage.
5.2.2.1 Configuring the Model CRX-6.5K for High Temperature Sample Stage Operation
If the optional HT stage was ordered with the Model CRX-6.5K probe station, the
removable stage will be installed and shipped in the probe station. In order to actively
control the HT stage, electrical connection must be made to the Model 336 tempera-
ture controller. The HT sample stage sensor will be connected to Input D of the
Model 336 temperature controller, instead of the CCR second stage sensor. Output 1
of the Model 336 will be reconfigured and used to control the HT sample stage.
5.2.2.1.1 Complete the Connections to the Probe Station
1. Disconnect the DIN style connector (labeled Sensor 1) that is connected to
Input D.
2. Disconnect the sample stage output control from the rear panel of the Model 336
temperature controller as follows:
a. Disconnect the banana style connector (labeled Heater 1) from Output 1.
b. Disconnect the green ground banana plug from the banana plug to the screw
terminal adapter.
