應用於毫米波的三五族半導體元件

III-V Semiconductor Devices for Millimeter-wave Applications

張翼 ； 涂永義 ； 游宏偉

《國家奈米元件實驗室奈米通訊》 23卷4期 (2016/12) Pp. 2-9

摘要

本文將描述過去在本實驗室所做的一些應用於毫米波的三五族半導體元件，包括GaAs PHEMT (Pseudomorphic High Electron Mobility Transistor)、GaAs MHEMT (Metaphorphic-HEMT)及InP HEMT。MHEMTs是結合數種晶格常數差異甚大之三五族磊晶材料，並利用緩衝層(Buffer Layer)來減少磊晶材料間Misfit Dislocation(差排)往上延伸至Active Layer的一種元件。然而，PHEMTs磊晶結構中材料間晶格常數都很接近，因此在磊晶過程中不需要成長很厚緩衝層(Buffer Layer)去防止Misfit Dislocation產生。InP的晶格常數與In_(0.53)Ga_(0.47)As及In_(0.52)Al_(0.48)As相當，在磊晶過程中不易產生Misfit Dislocation，可獲得較好磊晶品質。閘極沉降(Gate Sinking)的製程技術可減少源極和閘極之間半導體的電阻，並降低源極和閘極之間的電容(C_(gs))，進而改善了電晶體元件的射頻性能。複合通道結構解決了單一InGaAs通道的高銦含量所引起的低崩潰電壓問題，同時也保持了高銦含量具有的高電子遷移率優點。

關鍵字

砷化鎵 ； 磷化銦 ； 高速電子遷移電晶體 ； 假形高速電子遷移電晶體 ； 變晶型高速電子遷移電晶體 ； 閘極沉降 ； 埋入式閘極 ； 複合通道 ； 毫米波 ； W頻帶

並列摘要

In this paper, We report some of our previous work about III-V semiconductor devices for millimeter wave applications, including GaAs PHEMT (Pseudomorphic High Electron Mobility Transistor), GaAs MHEMT (Metaphorphic-HEMT), and InP HEMT. For MHEMTs, due to the lattice mismatch between each layer, a thick buffer layer is required to prevent misfit dislocations from extending into active layers. However, for PHEMTs, the lattice constant of each layer is very close, therefore, no thick bu_er layer is required to reduce the misfit dislocations during epitaxy. For InP HEMT, the lattice constant of InP matches that of In_(0.53)Ga_(0.47)As and In_(0.52)Al_(0.48)As, hence, a very good crystalline quality could be obtained. The gate sinking process can be applied to reduce the resistance and capacitance C_(gs) between source and gate, and the RF performance could be enhanced compared to processes without gate sinking. The composite channel design resolves the low breakdown voltage issue of a single InGaAs channel with high Indium content, and maintains the advantage of high electron mobility in the same time.

並列關鍵字

GaAs ； InP ； HEMT ； PHEMT ； MHEMT ； Gate Sinking ； Buried Gate ； Composite Channel ； Millimeter Wave ； W Band