Among different material technologies HgCdTe detectors offer significant advantages, when compared to other solutions. HgCdTe detectors provideВ  high detectivity, low bias voltage, selective peak wavelength response, and fast response times.В  High quality, high resolution HgCdTe imagers used in various applications of Laser Monitoring, Temperature Monitoring, Thermal Imaging, Industrial Process Control, Heat-Seeking Guidance and Laser Warning Receiver.

High resolutions HgCdTe imaging systems require built-in cooling for optimal performance. The frequency response of HgCdTe detectors is related to the Lifetime of the electrons in the HgCdTe crystal, and Lifetime depends on material composition and operating temperature. If regular detector types operate inВ  210-240K temperature range, where 2-stage or 3-stage thermoelectric cooling is applicable, premium types with high performance require deeper cooling below 200K, for instance at 180- 190K temperature range. And here the high performance 4-stage thermoelectric coolers are necessary.

HgCdTe detector manufacturers use different packaging solutions, when 4-stage thermoelectric cooler is applied. However, in this case typical solutions with TO-style headers are not suitable. 4-Stage TE cooler types have pyramidal shapes and bottom ceramics is usually too large to fit in regular and cheap TO-8 or TO-66 headers. Even standard TO-3 header isn’t suitable and has to be modified to fit the smallest standard 4-stage thermoelectric cooler. For instance 3CN packaging solution provided by one well-known photodetector manufacturer originally is a TO-3 header with customized pins placement, different to standard TO-3 type. 4-stage thermoelectric cooling solution for detectors require specialВ  packaging, that in most cases significantly more expensive and less flexible in terms of assembly interfaces for final product. The best way could be to reduce the size of thermoelectric cooler and fit it in a regular package types, but it was not possible with regular types of thermoelectric coolers till recently.

Standard 4-stage TEC for HgCdTe detectors, it’s compact analog from MD Series and High-Power Version

Each 4-stage Thermoelectric Cooler has five different height and performance options. Also TECs are provided with a variety of manufacturing options. Cold ceramics side can be blank or metallized. Alternatively customized Au patterns can be applied on the cold ceramics side of TE cooler. Thermoelectric Sub-assembly can be equipped with 10kOhm or 2.2kOhm thermistors for temperature control. TO-8 header can be of 6pins, 12pins and 16pins, with and without mounting screw. Any pinout configuration may be specified by Customer. Finally, the laser marking option is available for TO-8 Sub-Assemblies identification and process control.

Various manufacturing options provided for 4-stage Thermoelectric Sub-Assemblies on TO-8 headers