Summary form only given. When the gate length L/sub g/ of modulation-doped field-effect transistors (MODFETs) is reduced to deep sub-0.1 /spl mu/m range in pursuit of higher speed, it is most important to simultaneously reduce the gate-to-channel separation. The resulting high aspect ratio alleviates both the reduction of transconductance g/sub m/ resulting from drain-induced barrier lowering and the shift of threshold voltage V/sub th/. While the former point is essential for ultrahigh-speed ICs, the latter is the key to implementing enhancement-mode MODFETs (E-MODFET). However, the high aspect ratio is difficult to attain due to the enlarged side etching of gate grooves during recess etching, which leads to higher parasitic resistance. The electrochemical etching provides a feasible and easy-to-perform technology to form deep and narrow gate grooves for ultrahigh-speed MODFETs.
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机译：仅提供摘要表格。为了追求更高的速度，当将掺杂调制的场效应晶体管（MODFET）的栅极长度L / sub g /减小到小于0.1 sub / spl mu / m的深范围时，最重要的是同时降低栅极通道分离。所得到的高纵横比既减轻了由漏极引起的势垒降低引起的跨导g / sub m /的减小，又减轻了阈值电压V / sub th /的偏移。前者对于超高速IC是必不可少的，而后者是实现增强模式MODFET（E-MODFET）的关键。然而，由于在凹陷蚀刻期间栅极凹槽的侧向蚀刻的扩大，难以实现高的长宽比，这导致更高的寄生电阻。电化学蚀刻提供了一种可行且易于执行的技术，以形成用于超高速MODFET的深而窄的栅极凹槽。
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