磷化銦鎵高電子遷移率電晶體暨砷化銦鎵金氧半高電子遷移率電晶體於高頻與數位應用之探討

Abstract

不同載子參雜方式的磷化銦鎵高電子遷移率電晶體的高頻與數位特性在此被研究。在高頻無線通訊應用上，為了要提升線性度，載子被均勻參雜於蕭基層與參雜載子於通道層。以均勻參雜載子的方式製成之元件，三階交叉點可達22.19 dBm；通道參雜載子的方式製成之元件線性工作範圍達14.23 dB，並且三階交叉點電源損耗比值接近4.97。在數位邏輯應用上，均勻參雜載子的方式製成之元件可提升次臨線傳導斜率，以及開關電流比值；通道參雜載子的方式製成之元件的短通道效應也有所降低。 在數位應用時，高銦含量的砷化銦鎵通道材料是必須的，使元件能具有好的數位特性表現以及較高速的轉導特性。以原子層沉積氧化鋁做為閘極絕緣層也能降低漏電流並提高崩潰電壓。砷化銦鎵金氧半假晶式高電子遷移率電晶體和砷化銦金氧半高電子遷移率電晶體被製作出來並展現出良好的絕緣性。此外，將空橋結構應用於砷化銦金氧半高電子遷移率電晶體做出不同閘極寬度的元件，可做為數位應用上不同扇出層級之元件。

The RF and digital performance of InGaP/In0.22Ga0.78As pseudomorphic high electron mobility transistors (PHEMTs) with different doping profiles are investigated. In order to improve the device linearity for RF applications, the uniformly-doped and channel-doped structures are designed and the devices are compared. The uniformly- doped device shows higher IP3 of 22.19 dBm, and the channel-doped device shows higherΔ(IP3-P1dB) of 14.23 dB and higher IP3 to DC power consumption ratio (IP3/PDC) of 4.97 compared to other devices. Figures of merits of these devices for digital applications are also evaluated. SS and ION/IOFF ratio parameters can be improved by uniformly-doping in the Schottky layer and DIBL parameter can be reinforced by extra doping in the channel layer. For digital applications, the InGaAs channel with high indium concentration is required for better performance and higher transconductance. In addition, atomic layer deposition (ALD) Al2O3 is introduced to act as the gate insulator to reduce gate leakage current and increase breakdown voltage. Thus, the InAlAs/In0.7Ga0.3As metal-oxide-semiconductor metamorphic HEMTs (MOS-MHEMTs) and InAlAs/InAs MOS-HEMTs were fabricated and the insulating properties were improved. Moreover, the InAlAs/InAs MOS-HEMTs employing air-bridge structure with different gate widths exhibit similar threshold voltage, leading to the possibility for digital utilization of different fan-out level.