應用在氮化鎵高電子遷移率電晶體的銅閘極金屬阻障層之研究

Abstract

本論文探討使用氮化鈦(TiN)和氮化鎢(WNx)作為擴散阻擋層的銅閘極於高功率氮化鋁鎵(AlGaN)/氮化鎵(GaN)的高電子遷移率電晶體(High Electron Mobility Transistors, HEMTs)閘極金屬(gate metal scheme)之應用。使用銅製程閘極之元件和傳統鎳(Ni)/金(Au)閘極元件有相近的直流特性。在VDS=200V, VGS=-5V的偏壓條件應力(stress)測試下有優異的性能，其IDS和IGS並沒有顯著的改變。而在攝氏250度下，經1小時的熱穩定性測試(thermal stability test)後，使用氮化鈦(TiN)/銅(Cu)和氮化鎢(WNx)/銅(Cu)作為閘極金屬的蕭基能障高度(Schottky barrier height)也和傳統鎳(Ni)/金(Au)相似。總的來說，以氮化鈦(TiN)/銅(Cu)和氮化鎢(WNx)/銅(Cu)作為高功率氮化鋁鎵(AlGaN)/氮化鎵(GaN)的高電子遷移率電晶體(HEMTs)之閘極金屬的元件，在高偏壓之stress測試中，顯示出優異的直流特性、熱穩定性、穩定的電性表現。

In this study, the copper gate metal with the titanium nitride (TiN) and tungsten nitride (WNx) as a diffusion barrier layer on AlGaN/GaN high electron mobility transistors (HEMTs) were fabricated for high power application. To compare with the Ni/Au gate metal on AlGaN/GaN HEMTs, the Copper gate metal on AlGaN/GaN HEMTs was shown a similar direct-current (DC) characteristics. Moreover, the IDS and IGS characteristics of the Copper gate metal device were not significant reduction when measure at drain-source voltage of 200 volt and gate-source of -6 volt. Furthermore, the copper gate metal with the titanium nitride (TiN) and tungsten nitride (WNx) as a diffusion barrier layer on AlGaN/GaN HEMTs was shown DC properties similar to the Ni/Au gate metal on AlGaN/GaN HEMTs when measure the thermal stability test at 250 ℃for 1 hour. From the above results, the AlGaN/GaN HEMTs with the gate metal of the TiN/Cu and WNx/Cu was shown excellent DC characteristics, good thermal stability, and stable electrical performance at high bias stress testing.