The Effect of Hydrogen Treatment on Electrical Properties of AlGaAsSb
- PDF / 345,752 Bytes
- 6 Pages / 420.48 x 639 pts Page_size
- 14 Downloads / 244 Views
THE EFFECT OF HYDROGEN TREATMENT ON ELECTRICAL PROPERTIES OF AIGaAsSb. A.Y.POLYAKOV1 ,M.STAM 1 ,A.G.MILNES 1 ,R.G.WILSON 2 ,A.E.BOCHKAREV 3 ,P.RAI5 4 4 CHOUDHU Ry ,R.J.HILLARD ,S.J.PEARTON 1.ECE Department Carnegie Mellon University,Pittsburgh,PA 15213-3890,USA 2.Hughes Research Laboratories,250MS RL56,3011 Malibu Canyon Rd.,Malibu, CA 90265,USA 3.Institute of Rare Metals, B.Tolmachevsky,5,Moscow 109017,Russia 4.Solid State Measurements,inc., 110 Technology Drive,Pittsburgh,PA 15275,USA 5.AT&T Bell Laboratories,600 Mountain Ave.,Murray Hill,NJ 07974-2070,USA
ABSTRACT The effect of hydrogen treatment at 200 0 C on the concentration of electrically active defects in LPE grown AIGaAsSb is reported. In n-type layers the electrical properties are shown to be dominated by DX-like deep donors of three different types all of which are strongly passivated by the hydrogen treatment as evidenced by C-V,DLTS C-T and spreading resistance measurements. In p-type layers intrinsic acceptors of defect origin are also passivated by hydrogen. Deuterium profiles in both n- and ptype layers show characteristic plateaus indicative of formation of neutral compexes between hydrogen and dopants. Hydrogen treatment also leads to decrease of the Au/n-AlGaAsSb Schottky barrier height from 1.3 to 0.85 eV. INTRODUCTION. Hydrogen interaction with defects and impurities in III-V semiconductors is now relatively well studied[1-4]. However, the main bulk of experimental data refers to As and P containing compounds with very little known about hydrogen in Sb based III-V materials. In this paper we present hydrogen passivation studies in AIxGa1.x AsySbliy quaternary solid solutions which in combination with GaSb and InGaAsSb find important applications in lasers and photodetectors operating in the 24m wavelength range[5-7]. EXPERIMENTAL. Epitaxial layers of AIxGa1..xAsySbi.y used in this study were grown by LPE and were lattice matched to GaSb substrates. The composition of the layers as established by EDAX and photoluminescence was close to AI0. 5 Ga 0 .5 As 0 .0 4 Sb 0 .9 6 . The thickness of the layers was typically 3-4lim. N-type layers were doped with Te and p-type layers were nominally undoped. Characterization included C-V,C-T and DLTS measurements on Schottky diodes prepared by vacuum evaporation of variMat. Res. Soc. Symp. Proc. Vol. 262. 01992 Materials Research Society
426
ous metals. Details of sample preparation and measurements techniques will be presented in [8,9]. These capacitance measurements were complemented by twoprobe spreading resistance profiling (SRP) in which two lightweight specially conditioned kinematic probes are moved across a bevelled surface[10,11] to allow a depth resolution as high as 10-1 5A. Hydrogen or deuterium plasma treatments were performed in a parallel plate reactor(30kHz,0.08 W*cm- 2 ) at 200 0 C for 1 hour[1 2]. Secondary ion mass spectroscopy (SIMS) was performed using a 10 keV Cs+ ion beam. The depth scales were established by stylus profilometry of the resultant craters, and the concentration scale
Data Loading...
