Showing papers by "Adam William Saxler published in 2003"

Nitride-based transistors and methods of fabrication thereof using non-etched contact recesses

Abstract: Contacts for a nitride based transistor and methods of fabricating such contacts provide a recess through a regrowth process. The contacts are formed in the recess. The regrowth process includes fabricating a first cap layer comprising a Group III-nitride semiconductor material. A mask is fabricated and patterned on the first cap layer. The pattern of the mask corresponds to the pattern of the recesses for the contacts. A second cap layer comprising a Group III-nitride semiconductor material is selectively fabricated (e.g. grown) on the first cap layer utilizing the patterned mask. Additional layers may also be formed on the second cap layer. The mask may be removed to provide recess(es) to the first cap layer, and contact(s) may be formed in the recess(es). Alternatively, the mask may comprise a conductive material upon which a contact may be formed, and may not require removal.

3.5-watt AlGaN/GaN HEMTs and amplifiers at 35 GHz

Abstract: Sub-02-/spl mu/m AlGaN/GaN HEMTs were successfully scaled to 105 mm gate-width with minor gain reduction On-chip single-stage amplifiers exhibited gains of 8 dB and 75 dB, as well as output powers of 36 W and 35 W, at 30 GHz and 35 GHz, respectively This multi-watt output power at millimeter-wave frequencies well exceeded previous state-of-the-art for a GaN HEMT and is comparable to that from 6-7 times larger GaAs-based devices

Nitrogen passivation of interface states in sio2/sic structures

Abstract: A nitrided oxide layer on a silicon carbide layer is processed by annealing the nitrided oxide layer in a substantially oxygen-free nitrogen containing ambient. The anneal may be carried out at a temperature of greater than about 900 °C, for example, a temperature of about 1100 °C, a temperature of about 1200 °C or a temperature of about 1300 °C. Annealing the nitrided oxide layer may be carried out at a pressure of less than about 1 atmosphere, for example, at a pressure of from about 0.01 to about 1 atm or, in particular, at a pressure of about 0.2 atm. The nitrided oxide layer may be an oxide layer that is grown in a N2O and/or NO containing ambient, that is annealed in a N2O and/or NO containing ambient or that is grown and annealed in a N2O and/or NO containing ambient.

AlGaN-GaN HEMTs: material, device, circuit technology and applications

Abstract: The enabling features and performance of GaN based HEMTs as a high power, high bandwidth semiconductor technology are presented. Progress on materials development includes the development of AlGaN and AlN barrier HEMTs with room temperature electron mobility exceeding 2000 cm/sup 2//V-s. Trap free GaN HEMT devices with > 10 W/mm power density and devices with > 70 % efficiency are presented. Operation at > 200 /spl deg/C is reported. Simultaneous linearity and efficiency under class B is presented followed by discussion of mm-wave power performance. Finally, device scaling resulting in a total power > 100 Watts and GaN HEMT circuit demonstrations are presented including mm-wave amplifier with > 3 Watts at 30 GHz and 35 GHz.

Heterogeneous bandgap structures for semiconductor devices and manufacturing methods therefor

Abstract: Semiconductor devices include a wide bandgap semiconductor layer having an array of discontinuous wide bandgap semiconductor regions therein that contribute to a reduction in ionization energies of dopants in the wide bandgap semiconductor layer relative to an otherwise equivalent wide bandgap semiconductor layer that is devoid of the array of discontinuous wide bandgap semiconductor regions. The discontinuous wide bandgap semiconductor regions and the wide bandgap semiconductor layer have the same net conductivity type, but the discontinuous wide bandgap semiconductor regions are typically more highly doped to thereby provide excess charge carriers to the wide bandgap semiconductor layer.

Transistors a base de nitrure, et procedes de fabrication correspondants reposant sur l'utilisation de cavites de contacts etablies sans attaque

Abstract: L'invention concerne des contacts pour transistor a base de nitrure, et des procedes de fabrication correspondants qui visent a etablir une cavite par reformation. Les contacts sont constitues dans la cavite. La reformation consiste a realiser une premiere couche de couverture renfermant un materiau semiconducteur a nitrure d'element du groupe III. On elabore et on structure un masque sur la premiere couche. La structure du masque correspond a celle des cavites de contacts. On realise (developpe, par exemple) ensuite selectivement une seconde couche de couverture a nitrure d'element du groupe III sur la premiere couche de couverture, en utilisant le masque structure. On peut egalement former d'autres couches sur la seconde couche de couverture. Le masque peut etre retire, laissant une ou plusieurs cavites sur la premiere couche de couverture, et un ou plusieurs contacts peuvent etre realises dans la ou les cavites. En guise de variante, le masque peut renfermer un materiau conducteur sur lequel il est possible de realiser un contact, moyennant quoi ce masque ne doit pas etre retire.

Passivation a l'azote d'etats d'interface dans des structures de sio 2 /sic

Abstract: Cette invention concerne un procede de traitement d'une couche d'oxyde nitrure sur une couche de carbure de silicium consistant a recuire la couche d'oxyde nitrure dans un milieu ambiant contenant de l'azote sensiblement depourvu d'oxygene. Ce recuit peut etre effectue a une temperature superieure a environ 900 °C, par exemple a une temperature d'environ 1100 °C, d'environ 1200 °C ou d'environ 1300 °C. Le recuit de la couche d'oxyde nitrure peut etre effectue a une pression inferieure a environ 1 atmosphere, par exemple a une pression comprise entre environ 0,01 et 1 atm, en particulier a une pression d'environ 0,2 atm. Cette couche d'oxyde nitrure peut etre une couche d'oxyde qui est formee dans un milieu ambiant contenant N2O et/ou NO, qui est recuite dans un milieu ambiant contenant N2O et/ou NO ou qui est formee et recuite dans un milieu ambiant contenant N2O et/ou NO.