Bipolar Transistors in Small Bandgap Semiconductors

工作电压低于现有器件的双极晶体管将对无线通信和其他电池供电的应用产生重大影响。双极晶体管的工作电压由组成半导体的带隙决定，因此在低禁带半导体中需要双极晶体管。唯一具有比已用于双极晶体管的带隙更低的带隙的可行的半导体家族是所谓的6.1材料家族，以其晶格常数的值命名。异质结双极晶体管(HBT)是III-V半导体材料家族中流行的双极晶体管设计。在低禁带6.1材料中开发HBT似乎是很自然的，但这是不可能的。HBT与6.1版材料不兼容，因此需要另一种类型的双极型晶体管。这种晶体管就是隧道发射极双极晶体管(TEBT)。这个项目将研究低禁带隙6.1半导体中的TEBT。这项努力将沿着三条线进行：物理、材料和设备工程。物理涉及到TEBT所需的某些隧道过程。材料的工作是在6.1材料中开发用于TEBT的外延结构。TEBT的器件工程(以及制造和测试)最初将着眼于具有显著(40)DC电流增益的晶体管，后续将针对射频性能进行器件工程。

AbstractBipolar transistors that operate at a lower voltage than existing devices would have a big impact on wireless communications and other battery-powered applications. The operating voltage of a bipolar transistor is determined by the bandgap of the constituent semiconductor, thus bipolar transistors in low bandgap semiconductors are needed.The only viable semiconductor family with lower bandgaps than those already used for bipolar transistors is the so-called 6.1 material family, named after the value of their lattice constant.The heterojunction bipolar transistor (HBT) is the prevalent bipolar transistor design in III-V semiconductor material families. It would seem natural to develop HBT's in the low bandgap 6.1 materials, but this cannot be done. The HBT is incompatible with the 6.1 materials, so an alternate type of bipolar transistor is sought. Such a transistor is the tunneling emitter bipolar transistor (TEBT). This program will study the TEBT's in the low bandgap 6.1 semiconductors. The effort will be along three lines: physics, materials and device engineering. The physics involves certain tunneling processes required by the TEBT. The materials work is the development of the epitaxial structures for the TEBT in the 6.1 materials. The device engineering (and fabrication and testing) of TEBT's will initially aim at a transistor exhibiting a substantial (40) dc current gain, and follow up with engineering the device for rf performance.