A method of defectless dry etching of an AlGaN barrier layer is proposed, which consists in repeated plasmachemical oxidation of AlGaN and removal of the oxide layer by means of reactive ion etching in inductively coupled BCl3 plasma. Using the proposed etching technology, AlGaN/AlN/GaN high-electron-mobility transistors (HEMTs) with a buried gate have been successfully fabricated for the first time. It is shown that the currents of obtained HEMTs are independent of the number of etching cycles, while the gate operating point shifts toward positive voltages up to obtaining transistors operating in the enhancement mode.

AbstractA method of defectless dry etching of an AlGaN barrier layer is proposed, which consists in repeated plasmachemical oxidation of AlGaN and removal of the oxide layer by means of reactive ion etching in inductively coupled BCl_3 plasma. Using the proposed etching technology, AlGaN/AlN/GaN high-electron-mobility transistors (HEMTs) with a buried gate have been successfully fabricated for the first time. It is shown that the currents of obtained HEMTs are independent of the number of etching cycles, while the gate operating point shifts toward positive voltages up to obtaining transistors operating in the enhancement mode.

Field-effect high-electron-mobility transistors (HEMTs) based on AlGaN/AlN/GaN heterostructures with various gate lengths L g have been studied. The maximum values of current and power gaincutoff frequencies (f T and f max, respectively) amounted to 88 and 155 GHz for HEMTs with L g = 125 nm, while those for the transistors with L g = 360 nm were 26 and 82 GHz, respectively. Based on the measured S-parameters, the values of elements in small-signal equivalent schemes of AlGaN/AlN/GaN HEMTs were extracted and the dependence of electron-injection velocity vinj on the gate–drain voltage was determined. The influence of L g and the drain–source voltage on vinj has been studied.

Исследованы полевые транзисторы с высокой подвижностью электронов (HEMT) на основе AlGaN/AlN/GaN с разной длиной затвора Lg. Значения максимальных частот усиления по току fT и однонаправленного коэффициента усиления fmax составили 88 и 155 GHz для транзисторов с Lg =125 nm и 26 и 82 GHz для транзисторов с Lg = 360 nm соответственно. На основе измеренных S-параметров проведена экстракция значений элементов малосигнальных эквивалентных схем AlGaN/AlN/GaN HEMT и определена зависимость скорости инжекции vinj от напряжения затвор-исток. Также исследовано влияние длины затвора и напряжения между стоком и истоком на величину vinj. DOI: 10.21883/PJTF.2017.16.44927.16727

Field-effect high-electron-mobility transistors (HEMTs) based on AlGaN/AlN/GaN heterostructures with various gate lengths L (g) have been studied. The maximum values of current and power gaincutoff frequencies (f (T) and f (max), respectively) amounted to 88 and 155 GHz for HEMTs with L (g) = 125 nm, while those for the transistors with L (g) = 360 nm were 26 and 82 GHz, respectively. Based on the measured S-parameters, the values of elements in small-signal equivalent schemes of AlGaN/AlN/GaN HEMTs were extracted and the dependence of electron-injection velocity v(inj) on the gate-drain voltage was determined. The influence of L (g) and the drain-source voltage on v(inj) has been studied.

A technology for fabricating multifunction monolithic microwave integrated circuits (MMICs) based on gallium nitride (GaN) heterostructures, which operate at the frequency range up to 100 GHz (the Ka, V, and W bands), is developed. Power amplifier (PA) MMICs operating at 90 GHz are fabricated using the coplanar technology with the gain coefficient being up to 15 dB and the specific output power exceeding 500 mW/mm. In addition, microstrip technology with the use of the polymer dielectric and grounding metallization over the wafer surface without through holes in the substrate is approved. The parameters of the MMICs for multifunction single-chip transmit-receive modules (TRMs), as well as the parameters of the MMICs for intermediate-frequency amplifiers (IFAs), voltage-controlled oscillators (VCOs), low noise amplifiers (LNAs), PAs, and balanced mixers operating in the Ka and V bands (up to 70 GHz), which are fabricated using the proposed technology, are presented.