Modulation-doped β-(Al0.2Ga0.8)2O3/Ga2O3 field-effect transistor

Abstract

Modulation-doped heterostructures are a key enabler for realizing high mobility and better scaling properties for high performance transistors. We report the realization of a modulation-doped two-dimensional electron gas (2DEG) at the β-(Al0.2Ga0.8)2O3/Ga2O3 heterojunction by silicon delta doping. The formation of a 2DEG was confirmed using capacitance voltage measurements. A modulation-doped 2DEG channel was used to realize a modulation-doped field-effect transistor. The demonstration of modulation doping in the β-(Al0.2Ga0.8)2O3/Ga2O3 material system could enable heterojunction devices for high performance electronics.

Electron mobility in monoclinic β-Ga2O3—Effect of plasmon-phonon coupling, anisotropy, and confinement

“…Two-dimensional electron gas in β-Ga2O3 has been very recently demonstrated experimentally [33]. Theoretical mobility limits are not well known yet.…”

Deep level defects in Ge-doped (010) β-Ga2O3 layers grown by plasma-assisted molecular beam epitaxy

“…In spite of the early stage of development, promising device demonstrations have already been reported, including metal-semiconductor field effect transistors (MESFETs), 1 metal-oxide field effect transistors (MOSFETs), [2][3][4][5] Schottky diodes, [6][7][8][9] FinFETs, 12 delta-doped FETs, 13 and (Al 1-x Ga x ) 2 O 3 /Ga 2 O 3 modulation-doped field effect transistors (MODFETs) grown by plasma-assisted molecular beam epitaxy (PAMBE). 14,15 For these devices to evolve as theoretically predicted, controlled doping during epitaxy is critical and doping studies in b-Ga 2 O 3 are at an early stage for molecular beam epitaxy (MBE) growth. Promising n-type dopants for b-Ga 2 O 3 are Si, Ge, and Sn, since each is predicted to substitute on Ga sites.…”

Identification and modulation of electronic band structures of single-phase β-(AlxGa1−x)2O3 alloys grown by laser molecular beam epitaxy

“…6 Furthermore, (Al x Ga 1Àx ) 2 O 3 /Ga 2 O 3 based high electron mobility transistors (HEMTs) with a twodimensional electron gas channel has been demonstrated through Si delta-modulation doping. [7][8][9] Whereas the channel mobility is still not far enough for high frequency applications, as it is limited by polar optical phonon scattering due to a higher electron effective mass of 2DEG. 7 The device performance of photodetectors and transistors are normally determined by the optical transition nature and intrinsic effective mass, and therefore, a deep understanding of the fundamental properties of (Al x Ga 1Àx ) 2 O 3 alloying materials is critical.…”