Use of SiGe bipolar transistors for cryogenic readout of SQUIDs
Use of SiGe bipolar transistors for cryogenic readout of SQUIDs
复制标题
DOI：
10.1088/0953-2048/19/12/014
复制
发表时间：
2006-11
影响因子：
3.6
通讯作者：
M. Kiviranta
中科院分区：
文献类型：
--
作者：
M. Kiviranta
我们测量了四个商用的SiGe异质结双极晶体管在4.2K下的特性和噪声，其中一个器件在9 mW的功率损耗下显示了75PV Hz的−1/2白噪声和20 kHz的1/f噪声拐角，证明了它适合于读出浸入液体He中的SQUID。另一种器件在50µW的功耗下表现出370pV Hz的−1/2白噪声和5 kHz的1/f噪声拐角，在7µW的功耗下仍可提供可用的增益。该设备适用于用于制冷功率有限的闭路循环冰箱的鱿鱼多路复用器。可实现的耗散甚至可以在稀释式冰箱或ADR的低温阶段运行。在此基础上，实现了具有0.35μΦ0 Hz−1/2磁通噪声的SiGe基DC SQUID读出。施加负磁通反馈后，转换率超过50Φ0μS−1。
We have measured characteristics and noise of four commercially available SiGe heterojunction bipolar transistors at 4.2 K. One device exhibits 75 pV Hz−1/2 white noise and a 1/f noise corner of 20 kHz at 9 mW power dissipation, proving suitable for readout of SQUIDs immersed in liquid He. Another device exhibits 370 pV Hz−1/2 white noise and a 1/f noise corner of 5 kHz at 50 µW dissipation, and still gives useable gain at 7 µW dissipation. This device is useful for SQUID multiplexers intended for closed-cycle refrigerators, in which the cooling power is limited. The achievable dissipation is even compatible for operation in the low-temperature stages of dilution refrigerators or ADRs. Furthermore, SiGe-based dc SQUID readout with 0.35 μΦ0 Hz−1/2 flux noise was demonstrated. Applying negative flux feedback yielded a slew rate exceeding 50Φ0 μs−1.