The processing technique for microwave p – i – n diodes based on SiC (silicon carbide) has been developed. Based on these diodes, switches in the 3-cm range have been fabricated. It has been shown that the working power of the developed switches is about 10 times higher than that based on Si diodes at the same base thickness, which is equal to 5 μm. The ways of further improvement of the processing technique of these devices have been suggested.

Разработана технология СВЧ p-i-n-диодов на основе карбида кремния (SiC). С использованием данных диодов изготовлены переключатели для трехсантиметрового диапазона. Показано, что разработанные приборы по величине рабочей мощности примерно в 10 раз превышают рабочую мощность переключателей на базе Si-диодов при одинаковой толщине базы, равной 5 μm. Намечены пути дальнейшей оптимизации технологии данных приборов. Ключевые слова: карбид кремния, СВЧ диоды, модуляторы, переключатели, аттенюаторы.

The technology of microwave p-i-n diodes based on silicon carbide (SiC) has been developed. Using this diodes manufactured switches for 3-cm range. It is shown that the developed devices have an operating power of about 10 times the operating power of switches based on Si diodes with an equal base thickness of 5 microns. Outlined ways to further optimize the technology of these devices.

The design results of the solid-state Q-band low-noise receiver module with protection on synchronous and non-synchronous incident signals up to 1000 W impulse power are given. A bandwidth of the module is 6%, gain - 18 dB, noise factor - 4.6 dB, operating time - 0.2 μs.

The results of development of the autonomous semiconductor 8-mm wave length power limiter based on p-i-n - diodes matrix on Si and GaAs are presented. The device provides capacity for operation at input power up to 1 kW and at impulse power value over 0.7 W and response speed about 0.2 μs.

Multi-diode broadband microwave signal modulators based on 4H-SiC p-i-n diodes were fabricated and fully characterized. The three-diode modulators are characterized by a transmission loss of 1-2 dB and isolation of 27-34 dB in the 2-7 GHz frequency range. Two-diode modulators were specially designed for high-temperature operation. These modulators are characterized by a transmission loss of 1.1-2.6 dB and isolation of 33-44.5 dB, in the 2-7 GHz frequency range at temperatures up to 300°C.

4H-SiC p-i-n diodes were fabricated on epitaxial layers grown by Sublimation Epitaxy in Vacuum (SEV) and were evaluated for microwave power switching applications. Full electrical characterization (C-V, DC I-Vs, reverse recovery characteristics, low and high power microwave testing) has been performed. The results showed that SEV-grown SiC material is suitable for bipolar device fabrication. A doping higher than 1019 cm-3 for the p-type contact layer and lower than 1016 cm-3 for the n-type base layer is necessary to demonstrate microwave p-i-n diodes with similar performance as the ones fabricated on commercially available CVD-grown material.

The results of design of the Q-band low-noise receiver module with protection against synchronous and nonsynchronous incident signals up to 500 W impulse power and 20 W average power are given. A bandwidth of the module is 3 %, gain-18 dB, noise factor-4.2 dB, operating time-0.3 mus

4H-SiC p-i-n diodes were designed, fabricated and characterized for use in microwave applications. The diodes exhibited a blocking voltage of 1100 V, a 100 mA differential resistance of 1-3 &, a capacitance below 0.5 pF at a punchthrough voltage of 100 V and a carrier effective lifetime between 15-27 ns. Single 4H-SiC p-i-n diode switches, operating in X-band, exhibited insertion loss 0.7 dB, isolation up to 25 dB and were able to handle microwave power up to 2.2 kW in pulsed mode of operation. The switching speed of the switches has not exceeded 20 ns.

The possibility of fabricating heavily doped (N a −N d ≥ 1 × 1019 cm−3) p+-4H-SiC layers on CVD-grown lightly doped n-4H-SiC layers by sublimation epitaxy has been demonstrated. It is shown that a Au/Pd/Ti/Pd contact, which combines a low specific contact resistance (∼2 × 10−5 Ω cm2) with high thermal stability (up to 700°C), is the optimal contact to p-4H-SiC. The p-n structures obtained are used to fabricate packaged diodes with a breakdown voltage of up to 1400 V.

4H-SiC p-i-n diodes were designed, fabricated and characterized with the aim to be used for microwave applications. The best diodes with mesa structure diameters between 80 and 150 /spl mu/m, exhibited a blocking voltage of 1100 V, a 100 mA differential resistance of 1-2 /spl Omega/, a capacitance below 0.5 pF at punchthrough voltage of 100 V and carrier effective lifetime between 15-27 ns. X-band microwave switches based on 4H-SiC p-i-n diodes are demonstrated for the first time. The switches exhibited insertion losses as low as 0.7 dB, isolation up to 25 dB and operation in pulsed high microwave powers of 2.2 k W in isolation mode and 0.4 kW in insertion mode.

Thermal calculations of various design models of SiC p-i-n diodes with a structure capacity of 0.2 pF are carried out for substrate thicknesses of 360, 50, and 2 mm. Comparison with a silicon p-i-n structure on an integrated heat sink is performed.

4H-SiC p-i-n diodes with very good switching characteristics have been developed and used in high speed modulator in the Q-band range. The diode has a voltage drop at forward direction as low as 3.4 V at current density of 100 A/cm2. Leakage currents less than 1 muA are measured at reverse voltages of 1200 V and 1700 V in air and a SF6 atmosphere, respectively. The operating speed of the modulator is 5-7 ns which make it very perspective for applications in Q-band range. In the frequency range of 26-38 GHz, the modulator has insertion losses not more than 2 dB and isolation losses not less than 20 dB