Electronics at -108degC - Page 1
Forum section: electronics / projects

author: DenzilPenberthy
author_rank: Frequent Contributor
timestamp: August 04, 2022, 12:35:50 pm
content: Hi,I've got a project coming up which will need to operate at liquid Xenon temperature (about -108C). (FPGA plus some fast DACs and asosciated voltage regulators and stuff)I know I'm not going to find a huge number of devices/components which have datasheet info down to those temps. But does any one have any leads on resources (papers, app notes, books etc) that might give me clues on what components are likely to still work or what is going to be a non-starter? e.g. which capacitor dielectrics to look into etc. or tips for PCB design for thermal stress issues etc.Cheers,Denz.

author: m98
author_rank: Frequent Contributor
timestamp: August 06, 2022, 12:18:48 pm
content: Why would you need to immerse your electronics in liquid Xenon? Can't you just use some form of external probe for your measurements?

author: wraper
author_rank: Unknown
timestamp: August 06, 2022, 12:40:04 pm
content: https://sci-hub.se/10.1063/1.1472193https://sci-hub.se/10.1063/1.4939094

author: ejeffrey
author_rank: Super Contributor
timestamp: August 06, 2022, 05:15:33 pm
content: I know David Reilly has run xilinx FPGAs at Kelvin temperature ranges. It can be done, whether it is a good idea in a given situation is complicated.You also have to worry about the supporting components. High-k capacitors loose a big chunk of capacitance so you may end up bypassing with an absolutely absurd quantity of C0G capacitors. Voltage regulators, clocks, and other analog parts may stop working or change their properties a lot at cryogenic temperatures although -108C is not that cold and any active devices will self heat, possibly even back into the operating range.

author: RoGeorge
author_rank: Super Contributor
timestamp: August 06, 2022, 05:37:26 pm
content: Quote from: DenzilPenberthy on August 04, 2022, 12:35:50 pmThat is a very unusual request, what is the reason for which the electronic must operate in liquid Xenon?Normal parts won't work, and won't survive to temperature cycling. Then, the heat from the electronics has to be evacuated somehow. It will boil the liquefied gas. Are the cryogenic coolers able to evacuate the extra heat?

author: Kleinstein
author_rank: Super Contributor
timestamp: August 06, 2022, 06:04:42 pm
content: It would be really unusual to run digital electronics that cold (except going even colder and using superconducting logic - but that is totally different story).The main parts used cold are very low noise amplifier, AFAIK mainly with JFETs.

author: wraper
author_rank: Unknown
timestamp: August 06, 2022, 06:09:00 pm
content: Quote from: RoGeorge on August 06, 2022, 05:37:26 pmWhy not, most of them will, except certain types of components which will not work for sure. But you will need to actually test those components, especially semiconductors as their parameters may change a lot and some some ICs will just refuse to work properly at such temperature while others will work down to almost absolute zero. Barely any components have <-55oC rating not because they will not work but because barely anyone needs them. And guaranteeing such operation is an unjustified expense. And of course you better provide slow cooling, immersing warm PCB into a liquid xenon is not the best idea.

author: tggzzz
author_rank: Super Contributor
timestamp: August 06, 2022, 06:49:17 pm
content: I have zero experience in this area, so this is worth what you paid for it...There's no point in us speculating about whichtypeof components might work, since 99.99% of them will be irrelevant to yourunstatedobjectives. E.g. there's no point in us discussing transistors or resistors if you "need" to put a "processor" there, etc, etc!Start by finding other application domains with similar requirements, and see how they have approached the task.This sounds like a system design problem, where the starting point is to have as little as possible (whatever that might mean) at -108C. Work that out then you can start to figure out hoe to get it to work.I suspect that there will be many issues related to packaging, both inside the component and connecting components in circuits and systems. That was a major issue with Josephson Junction computer, even for IBM with its packaging prowess. And that raises a source of enquiry: how are the Josephson Junction voltage standards constructed.

author: SiliconWizard
author_rank: Super Contributor
timestamp: August 06, 2022, 06:53:42 pm
content: One problem beyond the semiconductors used will be PCBs and reliability of assembly at such temperatures.

author: tggzzz
author_rank: Super Contributor
timestamp: August 06, 2022, 07:58:21 pm
content: Some starting points, especially cryogenic application domainshttps://www.sensortips.com/featured/electronics-that-operate-in-cryogenic-cold/

author: ejeffrey
author_rank: Super Contributor
timestamp: August 06, 2022, 08:14:37 pm
content: As a general rule, FETs will work cold but the threshold will change and the gain will go up. BJTs will not as they loose hFE at low temperature and eventually (much colder than -108) have carrier freeze out. Most any simple CMOS logic (e.g., 74HC...) will work cold but the timing will change so the FPGA tool timing analysis will be wrong. If you run well below fMax that doesn't have to be a problem.Voltage regulators, oscillators and PLLs, current sources, and other analog parts may either stop working or significantly change operating parameters enough to cause a problem. This might be an issue for things like the DAC current reference. You may be better off locating a lot of your support circuitry (voltage regulators and clocks) at room temperature.Many passives will work although high-k ceramic capacitors will loose a big chunk of their capacitance. If you go a lot colder (4 K) then resistors become a problem: some go massively up in resistance, others become superconducting. Nichrome thin film resistors are a good choice, they will work fine down to ultra-low temperature.For thermal contraction, it's not usually a problem with small chips especially leaded chips, but high pin count BGAs and leadless chips may be a problem. You may need to find a PCB material closer matched to your chip packaging.When running signals and power to a cryogenic system, there is a tradeoff between electrical and thermal conductivity, so you can't usually use as low resistance wire as you want. For colder operation you normally have to use alloys like brass or copper-nickel. So for power supplies you should plan on using 4 wire remote sensing.-108C isn't that cold. A lot of stuff will probably work fine. Active components will self-heat, possibly even back into their operation range. But it is all out of manufacturers spec, so you will have to qualify everything yourself. Also this makes dealing with obsolete parts even more annoying as changes that don't affect room temperature operation can totally screw you. It's best as soon as any part is qualified to buy a lifetime supply.

author: mawyatt
author_rank: Super Contributor
timestamp: August 06, 2022, 09:42:43 pm
content: Quote from: ejeffrey on August 06, 2022, 08:14:37 pmThis statement is incorrect, as Silicon Germanium Bipolar Transistors, or SiGe BJTs indeed operate very well at colder temperatures. Dr. John Cressler at Georgia Tech University demonstrated a SiGe BJT 130nm device operating ~4 Kelvin with a Fmax of ~800GHz back in 2014 (likely well over 1THz today).After some of our earlier work back ~2004, we alerted and supplied Dr Sandy Weinreb at JPL with 130nm IBM 8HP SiGe BJT devices for use in cooled (77K) MW/MMW Low Noise Amplifiers for radio telescopes arrays, see S. Weinreb, J. Bardin, and H. Mani, “Design of Cryogenic SiGe Low- Noise Amplifiers,” IEEE Trans. Microw. Theory Tech., vol. 55, no. 11, pp. 2306–2312, nov 2007.Here are a few references on operating SiGe BJTs at cold temperatures.https://siliconsemiconductor.net/article/79450/Is_SiGe_transistor_cooler_than_III-Vshttps://www.ihp-microelectronics.com/php_scripts/publications/manuscript_files/ruecker-ieee-bctm-2017-accepted-2019.pdfhttps://ieeexplore.ieee.org/stamp/stamp.jsp?arnumber=9624975Best,

author: LM21
author_rank: Regular Contributor
timestamp: August 07, 2022, 06:38:28 pm
content: This statement is incorrect, as Silicon Germanium Bipolar Transistors, or SiGe BJTs indeed operate very well at colder temperatures. Dr. John Cressler at Georgia Tech University demonstrated a SiGe BJT 130nm device operating ~4 Kelvin with a Fmax of ~800GHz back in 2014 (likely well over 1THz today).Off topic sorry. I read elsewhere that transistors stop working at plasma frequency. How high that is?