Gate-recessed AlGaN-GaN HEMTs for high-performance millimeter-wave applications

Abstract

We report deep-submicrometer gate-recessed and field-plated AlGaN-GaN HEMTs and their state-of-the-art continuous wave (CW) power performance measured at 30 GHz. The AlGaN-GaN HEMTs exhibit a CW power density of 5.7 W/mm with a power-added efficiency (PAE) of 45% and drain-efficiency of 58% at ds = 20 V. At ds = 28 V, the output power density is measured as high as 6.9 W/mm with both PAE and output power increasing with input power level. Compared to conventional T-gated AlGaN-GaN HEMTs, the output power density and PAE of gate-recessed AlGaN-GaN HFETs are improved greatly, along with the excellent pulsed IVs. We attribute the improvement to both a field-plating effect and a vertical separation of the gate plane from surface states.Index Terms-Field-effect transistor (FET), GaN, HEMT, millimeter-wave (mmWave).

Control of Threshold Voltage of AlGaN/GaN HEMTs by Fluoride-Based Plasma Treatment: From Depletion Mode to Enhancement Mode

“…However, a compatible wet-etching method for AlGaN/GaN is still lacking up to now. As an alternative approach, a chloride-based dry inductively coupled plasma reactive ion etching (ICP-RIE) has been employed to fulfill such a task by several groups [15]- [20]. This approach can effectively modify the V th of AlGaN/GaN HEMT to positive direction.…”

AlN/GaN-гетероструктуры для нормально закрытых транзисторов

“…На рис. 3 показана эволюция картин ДБЭ, измеренных в направлении [11][12][13][14][15][16][17][18][19][20] Холловская подвижность двумерных электронов в SiN/AlN/GaN-ГЭС при комнатной температуре состав-ляла µ = 1200 см 2 /В · с при концентрации электронов n e = 1.1 · 10 13 см −2 .…”

“…Одним из наиболее перспективных направ-лений воспроизводимого получения Е-HEMT является использование AlN/GaN-гетероструктур со сверхтонким z, nm (менее 6 нм) барьером [11]. Другие подходы получе-ния Е-HEMT, такие как рост AlGaN/GaN-ГЭС с тон-ким (10 нм) AlGaN-барьером [12], стравливание части AlGaN-барьера, расположенной под затвором [13,14], формирование p−n-перехода под затвором [15], об-работку AlGaN-барьера во фторидной плазме [16], рост N-полярных ГЭС [17], не обеспечивают необходи-мой однородности, воспроизводимости и стабильности приборов. В настоящей работе представлены результаты раз-работки конструкции и технологии выращивания AlN/GaN-ГЭС для Е-HEMT.…”

Formation of combined partially recessed and multiple fluorinated-dielectric layers gate structures for high threshold voltage GaN-based HEMT power devices

“…To simplify circuit design and provide a better fail-safe operation in the power switching applications, a normally-off mode with a large threshold voltage (V th > 3 V) is required. Recently, various approaches such as gate recess etching [11][12][13][14][15], fluorinated gate or gate dielectric [16][17][18][19][20][21][22][23][24], and p-gate cap layer [25][26][27] have been explored to realize the normally-off operation. However, there are still several shortcomings in these devices.…”