p-type Ge-channel MODFETs with high transconductance grown on Si substrates

Author

König, U. ; Schäffler, F.

Author_Institution

Daimler-Benz AG, Ulm, Germany

Volume

14

Issue

4

fYear

1993

fDate

4/1/1993 12:00:00 AM

Firstpage

205

Lastpage

207

Abstract

Modulation-doped FET (MODFET) structures with hole channels consisting of pure Ge were grown by molecular beam epitaxy (MBE) on Si substrates. To overcome the relatively large lattice mismatch, between Si and Ge, a relaxed Si/sub 1-x/Ge/sub x /buffer layer with linearly graded Ge concentration and a final x value of around 70% was grown first. Hall mobilities of up to 1300 cm/sup 2//V-s at room temperature and 14000 cm/sup 2//V-s at 77 K were measured. Devices with and without gate recess were fabricated, which result in enhancement- and depletion-type FETs. Maximum extrinsic transconductances of 125 and 290 mS/mm at room temperature and 77 K, respectively, were found for gate lengths L/sub G/ around 1.2 mu m.<>

Keywords

Ge-Si alloys; Hall effect; carrier density; elemental semiconductors; germanium; high electron mobility transistors; molecular beam epitaxial growth; semiconductor growth; silicon; 1.2 micron; 125 mS/mm; 290 mS/mm; 300 K; 77 K; Ge-Si/sub 1-x/Ge/sub x/-Si; Hall mobilities; I-V characteristics; MODFET; Si substrates; carrier density; depletion-type FETs; enhancement type FET; gate lengths; gate recess; high transconductance; hole channels; lattice mismatch; linearly graded Ge concentration; molecular beam epitaxy; relaxed buffer layer; Buffer layers; Epitaxial layers; FETs; HEMTs; Lattices; MODFETs; Molecular beam epitaxial growth; Substrates; Temperature; Transconductance;

fLanguage

English

Journal_Title

Electron Device Letters, IEEE

Publisher

ieee

ISSN

0741-3106

Type

jour

DOI

10.1109/55.215149

Filename

215149