Bipolar Transistors in Small Bandgap Semiconductors

工作电压比现有器件低的双极晶体管将对无线通信和其他电池供电应用产生重大影响。双极晶体管的工作电压由组成半导体的带隙决定，因此需要低带隙半导体的双极晶体管。唯一可行的比已经用于双极晶体管的带隙更小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族半导体材料中最流行的双极晶体管设计。在低带隙6.1材料中发展HBT似乎是很自然的，但这是不可能的。HBT与6.1材料不兼容，因此寻求双极晶体管的替代类型。这种晶体管就是隧道发射极双极晶体管（TEBT）。本程序将研究低带隙6.1半导体中的TEBT。这项工作将沿着三个方向进行：物理、材料和设备工程。物理过程涉及到TEBT所要求的某些隧穿过程。材料方面的工作是开发6.1材料中TEBT的外延结构。TEBT的设备工程（以及制造和测试）最初的目标是晶体管表现出可观的（40）直流电增益，然后进行射频性能的设备工程。

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.