应用于PHEMT器件的深亚微米T形栅光刻技术

Deep-submicron T-shaped gate lithography technology for PHEMT device

PHEMT器件和基于它的高频单片集成电路广泛应用于现代微波/毫米波系统。当PHEMT器件的栅长缩短到足够短的时候,沿着栅宽方向的寄生电阻会影响PHEMT器件的性能。为了解决这个问题,一种具有大截面面积而底部长度却很小的T形栅结构通常被用于制作PHEMT器件,因为这种结构可以有效地减少由于栅寄生电阻而引起的晶体管噪声。对几种常用的制作深亚微米T形栅的三种光刻技术即光学光刻、电子束光刻、X射线光刻技术进行了比较分析。对于光学光刻技术,通常需要采用移相和光学邻近效应校正技术,它的制作成本低,但是很难用于制作深亚微米T形栅;对于电子束光刻技术,通常需要采用高灵敏度和低灵敏度的多层胶技术,虽然它的栅长可以制作到非常小,但是它的生产成本非常高,而且它的生产效率非常低;对于X射线光刻技术,它不仅可以用于制作深亚微米T形栅,而且它的生产效率非常高,T形栅的形状可以非常容易控制。

Pseudomorphic high electron mobility transistor(PHEMT )device and its incorporation in high frequency monolithic integrated circuits are widely used in modern microwave /millimeter-wave system.While the gate length of PHEMT device is adequately short,the parasitic resistance across the width of the gate limits the PHEMT device performance.Consequently,T-shaped struc-ture which have a large cross-sectional area but a short footprint has been applied for the fabri-cation of PHEMT device,because it is effective in reducing transistor noise due to gate parasitic resistance.In this paper,Three lithography technologies namely optical lithography,e-beam lithog-raphy and X-ray lithography used to fabricate deep-submicron T-shaped are analysed and com-pared.For optical lithography,both phase-shift and optical proximity correction technology are of-ten used,it is cheap,but it is hard to fabricate deep-submicron gate;for e-beam lithography,multiple layers of high and low sensitivity resists are often used,although it can be used to fab-ricate deep-submicron easily,its cost is very high and its throughout is very low;for X-ray lithography,it can be used to fabricate deep-submicron easily,and its throughout is high,it is sufficiently flexible to enable the T-gate shape variation to be achieved in a well-controlled man-ner.