I N Arsentiev\ A E Belyaev^, A V Bobyl\ N S Boltovets^, V N Ivanov^, V M Kovtonyuk^,

R V Konakova^, Ya Ya Kudryk , V V Milenin^, I S Tarasov\ E P Markovskyi^, R A Red’ko^, E V Russu^

^Ioffe Physico-Technical Institute RAN 26 Politekhnicheskaya St, Sankt-Peterburg, 194021 Russia e-mail: arsentyev@mailiofferu Ph: +{7-812) 247-91-34 ^V Lashkaryov Institute of Semiconductor Physics of the National Academy of Sciences of Ukraine

41 Nauki Prosp, Kiev, 03028, Ukraine e-mail: konakova@ispkievua Ph: +{380-44) 525-61-82 ^State Enterprise Research Institute “Orion”

8a Eugene Pottier St, Kiev, 03057, Ukraine e-mail: bms@ikievua Ph: +{380-44) 465-05-48 ^Institute of Applied Physics ANM 5 Academia St, Kishinev, MD-2028, Moldova e-mail: rusue@lissesasmmd Ph: +{373-2) 73-90-48

Fig 1 Layout ofthe diode structure

Abstract – We developed (i) a technology to form Au-Ge- TiBx-Au ohmic contacts to indium phosphide Gunn diodes on the basis of n-n^-n^^ epitaxial structures made on the standard and porous n^^-lnP substrates, (ii) batch-fabrication technique for mesas with gold heat sink, and (iii) technique for diode chip packaging in a metal-quartz package It is shown that the Gunn diodes of both types (on the standard and porous substrates) ensure generation of microwave power in the 88-98 GHz frequency range When operating under normal climatic conditions and at a temperature no less than -40 °C, the power output Pout of the Gunn diodes made on the porous substrates is over that of the ones made on the standard substrates At package temperature of +75 °C, the power output of the Gunn diodes of both types decreases, with Pout value of the diodes made on the porous substrate becoming somewhat below that of the ones made on the standard substrate We suppose that the reason for Pout decrease is the temperature dependence of thermal conductivity which is different in the standard and porous InP

I                                    Introduction

Fig 2 Structural diagram of measurement of microwave diode parameters: 1 – oscillator for measurement ofthe diode parameters 2 – voltammeter M2038 3 – power supply source 13PP-30-30-004 4 – voltmeter B7-40

5 – waveguide channel 6 – receiving transducer ПП-13 7 – power meter M3-75 8 – spectrum analyzer C4-27

9 – frequency meter

Indium phosphide attracts developers by a real possibility to expand operating frequency range of the microwave Gunn diodes [1, 2] To this end, attempts were made to improve the manufacturing technologies for InP epitaxial layers, various chip designs and packaging techniques are being developed, and new contact systems are advanced In our previous works we reported on application of InP epitaxial layers grown on porous substrates in the Gunn diode technology It was found that the InP active layers formed on such substrates have more perfect structure, and application of antidiffusion (quasi) amorphous TiBx layers in contact metallization increases the degradation temperature limit [3, 5] Here we consider the output parameters of Gunn diodes made on the basis of InP epitaxial layers grown on the standard and porous substrates

II        Sample and Experimental Procedure

A multilayer Au-Ge-TiB>r-Au contact was formed on the surface of the n-n*-n** epitaxial structures grown on the standard n**-\nP substrates and porous ones that were prepared according to the technological procedure described in [3, 4] The charge carrier concentrations (thicknesses) in the η-, n * – and n * “-layers were ~ 2×10 ^ ®, 5×10 ^ ^ and <2×10 ^ ® cm ® (~ 1.5, 3 and 350 ЦТ), respectively.

The contacts were layer-by-layer deposited using the magnetron sputtering technique, in a single technological cycle, without vacuum failure The setup used for contact deposition was an updated plant УВН-75р with oil-free evacuation The contact-forming layers were deposited in the argon atmosphere at a pressure of 04 Pa Our investigations of the contact parameters and morphology showed that the best contact resistivity (pc ^ 10 ® Ω-cm ^) is obtained when the thicknesses of the Au, Ge and TiBx films are 018, 003 and 01 ЦТ, respectively, that of the upper Au layer is 02 ЦТ, and thermal treatment in the hydrogen atmosphere is performed at a temperature ~500 °C

The Gunn diodes were made using the batch-fabrication technique for mesas with an integral gold heat sink on the side of the cathode contact The diode structures (diameter of 80 ЦТ) were fabricated using photolithography (Fig 1)

Те ensure the Gunn diode operating frequency, the package resonance frequency should be over the operating one That is why the diode chips were mounted in a metal-quartz package The manufacturing technology for diode packages with quartz bushes has been developed at the State Enterprise Research Institute «Orion» It ensures package capacitance of 004 pF and diode package resonance frequency over 150 GHz

The microwave diode characteristics were measured at a test bench (see Fig 2) The measuring chamber was a 18×36 mm waveguide section shorted with a movable piston on one side The diode was supplied through a low-pass filter The diode tuning at a certain and maximal power was performed by piston motion and diode travel throughout the height of the waveguide The measurements were carried out under normal climatic conditions, at temperatures of-40 °C and +75 °C

III                     Result of Measurements

Shown in Fig 3 are the typical frequency and temperature dependencies of the power output Pout for the diodes made on the InP epitaxial layers that were grown on the standard and porous η·&quot·&quot-ΙηΡ substrates

F , GHz

d’

Fig 3 Power output as function of frequency and temperature for diodes made on the inP epitaxiai iayers

grown on a standard (dashed curve) and porous (fuii curve) n**-inP substrates

One can see from Fig 3that, when operating under normal climatic conditions and at a temperature of – 40 °C, the power output Pout (in the 88-98 GHz frequency range) of the Gunn diodes made on the porous InP substrates is over that of the ones made on the standard substrates As temperature grows, the difference between the Pout values for the Gunn diodes of both types decreases, and at package temperature of +75 °C, the power output ofthe diodes made on the porous substrates becomes lower than that of the ones made on the standard substrate It seems to us that this fact may be related to the temperature dependence of phosphide indium thermal conductivity which may be different in the standard (nonporous) and porous materials

The experimental data on the temperature dependence of porous InP thermal conductivity are practically unknown Therefore it seems expedient to study the effect of thickness of porous layer of substrate InP (in our experiment it did not exceed 12 ЦТ) on the Gunn diode power output measured over a frequency range at different diode package temperatures

IV                                    Conclusion

Thus, our investigations demonstrated the possibility to make indium phosphide Gunn diodes on the basis of InP epitaxial layers that were grown on the porous InP substrates Under the normal climatic conditions, these diodes have higher Pout values in the 88-98 GHz frequency range than similar Gunn diodes made using the standard material

V                                     References

[1]  H Eisele, R Kamoua Submillimeter-wave InP Gunn devices IEEE Trans MTT 2004 v 52 N 10 p2371-2378

[2]  H Eisele, A Ritberg, G I Haddad Recent advances in the performance of InP Gunn devices and GaAs TUNNETT diodes for the 100-300 GHz frequency range and above

IEEE Trans MTT 2000 v 48 N 4 p626-631

[3] AA Sitnikova, A У Bobyl, SG Konnikov, VP Ulin The features of formation of epitaxial films on porous lll-V substrates Semiconductors 2005 v 39 N 5 p522-556

[4] IN Arsentiev, A У Bobyl, SG Konnikov, IS Tarasov,

V P Ulin, M V Shishkov, N S Boltovets, V N Ivanov,

A E Belyaev, R V Konakova, Ya Ya Kudryk,

A B Kamalov, P M Lytvyn, E P Markovskyi, V V Milenin, R A Red’ko Porous nanostructured InP: technology, properties, application: Semicond Phys, Quantum Electron &amp Optoelectron 2005 v 8 N 4 p95-104

[5]  / N Arsentiev, A E Belyaev, N S Boltovets, V N Ivanov, R V Konakova, S G Konnikov, Ya Ya Kudryk,

V V Milenin, I S Tarasov, E P Markovskyi, E V Rusu New technological possibilities for formation of GaAs and InP epitaxial layers for Gunn diodes Proc 15&quot’ Int Crimean Conf «Microwave and Telecommunication Technologies» 12-15 Sept 2005 Sevastopol: Veber 2005 p 633-634

ФІЗИКО-ТЕХНОЛОГІЧНІ ОСОБЛИВОСТІ ВИГОТОВЛЕННЯ І ПАРАМЕТРИ InP ДІОДІВ ГАННА КОРОТКОГО міліметрового діапазону довжини хвиль

І Н Арсентьев, А Є Бєляєв, А В Бобир,

Н С Болтовець, В Н Іванов, В М Ковтонюк,

Р В Конакова, Я Я Кудрик, В В Міленін,

І С Тарасов, Є П Марковський, Р А Редько,

Є В Руссу

Анотація – Розроблено технологію формування омічних контактів Au-Ge-TIBx-Au до фосфідіндіевим диодам Ганна на основі п-п *-п ** епітаксійних структур, виготовлених на стандартних і пористих підкладках п * – 1пр, групова технологія виготовлення мезаструктур із золотим теплоотводом і технологія корпусирования діодних чіпів в металлокварцевий корпус Показано, що діоди Ганна обох типів (на стандартних і пористих підкладках) генерують НВЧ потужність в діапазоні частот 88 – 98 ГГц При роботі в нормальних кліматичних умовах і при температурі не нижче -40 ° С вихідна потужність Р вих діодів Ганна, виготовлених на пористих підкладках, вище, ніж у діодів Ганна на стандартних підкладках При температурі корпусу +75 ° С вихідна потужність діодів Ганна обох типів зменшується, але в діодах на пористої підкладці Рвих стає дещо менше в порівнянні з діодами Ганна на стандартній підкладці Передбачувана причина зменшення Рвих обумовлена ​​температурної залежністю теплопровідності, різної в пористому матеріалі і в стандартному InP

Джерело: Матеріали Міжнародної Кримської конференції «СВЧ-техніка і телекомунікаційні технології», 2006р