利用電子束微影改變 T 型閘極對於 90 奈米砷化銦高電子遷移率電晶體電性影響之研究

Abstract

由於三五族砷化銦材料的高電子遷移率以及絕佳的能帶設計，取 代原本的矽材料達到高速、高頻、低耗能的元件特性，再者，藉由複 合通道的設計，提高通道的銦含量提升元件的飽和電流以及短通道效 益之抑制，讓三五族砷化銦材料應用於高速、高頻的數位電路以及低 雜訊等應用有良好的發展。 在此研究中，成功的製作了九十奈米T型閘極線寬的砷化銦高電 子遷移率電晶體，透過電子束微影兩次曝光以及以低溫顯影的方式達 到微縮元件線寬的目的，就此提升元件的電流、轉導以及高頻的特性。 在此研究當中，將會介紹電子束微影的物理機制以及製程手法之改 變，另外透過元件設計之閘極頭寬的電性結果，可以清楚了解如果為 了達到上述之高轉導、高頻特性之元件，必須同時微縮閘極線寬以及 閘極頭寬來達到目的，在此研究，九十奈米的砷化銦高電子遷移率電 晶體成功表現高增益、高頻以及良好的數位邏輯特性。

Due to the high electron mobility and superior band gap design, InAs HEMT has substituted Si to achieve high speed, high frequency and low power consuming performance. Furthermore, with the design of bounded channel, we enhance the percentage of the Indium content in the channel. The purpose is particularly to enhance device saturate drain current and restrain short channel effect. InAs material HEMT is nowadays used in the application of high speed, high frequency digital circuits and low noise developments. In this study, the 90 nm T-shaped InAs HEMTs have been successfully fabricated. Through two-time exposure of E-beam lithography and low temperature E-beam photoresists development, I have established the stable process of scaling the T-shaped gate length. The gate structure is used to enhance high current, high transconductance and high frequency properties. The mechanism and the challenges of E-beam lithography will be discussed in this study. Also, an additional characteristics discussion will be given in the study with the designing of T-shaped gate head dimension. In order to get better characteristic properties of transconductance and frequency, we have to scale down the gate length and gate head dimension. In this study, the 90nm InAs HEMTs successfully showed high speed, high transconductance and high frequency properties.