[ NEW ] Thermal Desorption Spectrometer with Integrated Bandgap Monitor
ESCO-TDS1200II IR BGM
ESCO-TDS1200Ⅱ IR BGMOffering a new option of direct sample temperature determination for rapid heating and low-temperature range measurements.
The ESCO-TDS1200II IR BGM is a model equipped with a bandgap monitor, based on the ESCO-TDS1200II IR, an infrared lamp heating thermal desorption spectrometer.
As with conventional models, thermal desorption analysis over a wide temperature range from room temperature to 1200°C is possible using thermocouple measurement.
In addition, by utilizing the bandgap monitor, it is now possible to optically determine the sample temperature directly for samples containing a silicon substrate in the range of approximately 75°C to 500°C.
[ Basic Performance of the ESCO-TDS1200II IR BGM ]
The conventional ESCO-TDS1200II IR employs a structure that intensively irradiates light from an infrared lamp around the sample.
・Rapid heating at 60°C/min
・Short measurement time of approximately 20 minutes per run
・Suppression of chamber heating through sample-centered heating
・Cooling time after heating of approximately 1 to 1.5 hours
The ESCO-TDS1200II IR BGM maintains all of these outstanding features.
The bandgap monitor is a temperature determination system that utilizes the property of silicon's bandgap changing in dependence on temperature.
Through spectroscopic analysis of transmitted light, it directly determines the temperature of samples containing a silicon substrate, such as a sample with a thin film formed on the silicon substrate surface.
Because the sample temperature can be determined at high speed, precise temperature control is possible even under rapid heating conditions.
By combining the following:
・Infrared lamp heating
・Temperature determination by the bandgap monitor
・Feedback control of lamp power based on temperature information
...this system expands the options for temperature control in thermal desorption spectroscopy.
Figure 1Schematic diagram of the TDS system equipped
with a bandgap monitor (Figure 1)
Broadband white light, ranging from the visible to the near-infrared region emitted from a light source,
passes through a high-purity quartz rod and irradiates the silicon sample placed on a quartz sample stage inside the ultra-high vacuum chamber.
A spectroscopic detector then receives a portion of the transmitted light from the silicon through an optical receiving window.
Application Examples
[1] Evaluation of Surface Water on Oxide Films
Through measurements using the bandgap monitor, the bonding states of water present on the oxide film surface can be evaluated based on differences in desorption temperatures.
□ Physisorbed water desorbing in the low-temperature range
□ More strongly bonded water-related species desorbing in the mid- to high-temperature range
Fig. 2It becomes possible to clearly separate and evaluate these based on their distinct desorption temperatures.
Therefore, this is highly useful for investigating processes where surface water plays a critical role, such as wafer-level hybrid bonding.
We prepared a sample by implanting hydrogen ions at a dose of 1.1 × 1017 cm-2 with an acceleration energy of 40 keV into a p-type (100) silicon substrate on which a 10 nm thick SiO2 film was formed.
Upon analyzing the desorption behavior of H2O molecules, three desorption peaks were observed at around 168°C, 315°C, and 398°C.
The peak on the low-temperature side is considered to correspond to physisorbed water, while the two peaks on the high-temperature side correspond to hydroxyl groups and internal water.
This system makes it easy to separate the contributions of physisorbed water and more strongly bonded water, making it extremely useful for evaluating the H2O adsorption state on the surface. (Figure 2)
[2] Oxide Semiconductor Thin Films (IGZO, etc.)
It is capable of evaluating the desorption behavior of water-related species and metal components, which can be utilized to investigate and optimize heat treatment conditions in thin-film processes.
Summary
The ESCO-TDS1200II IR BGM provides a new means to directly determine the sample temperature in the range of approximately 75°C to 500°C, while maintaining the high-throughput advantage of the conventional system.
It expands the options for temperature evaluation in thermal desorption spectroscopy, broadening the possibilities for advanced material evaluation and process development.
