Surface oxidation and chlorination of GaAs(100)

Thesis/Dissertation · Mon Dec 31 23:00:00 EST 1990

OSTI ID:5650201

Ludviksson, A

The use of nitrogen oxides (NO[sub 1]NO[sub 2] and N[sub 2]O) is a feasible alternative to oxygen for the oxidation of gallium arsenides, due to lower bond strength and the open shell character of some of these molecules. NO and NO[sub 2] very efficiently oxidize the GaAs(100) surface and require orders of magnitude smaller exposures than molecular oxygen to form a complete oxide layer on the surface. The oxidation efficiency of the GaAs(100) surface is found to be NO[sub 2] > NO [much gt] N[sub 2]O, O[sub 2], where N[sub 2]O produced no surface oxidation in the range of this work. The NO reacts nearly completely to form N[sub 2]O and surface oxide at LN[sub 2] temperature, but dosing the clean surface at 300 K gives no measurable NO adsorption or surface oxidation. The adsorption of NO[sub 2] at LN[sub 2] temperature forms surface oxide, but unlike NO, the oxidation process is also efficient at room temperature. Chlorine is the most frequently used reagent in dry etching of GaAs, which can be attributed to its high reactivity and to the volatility of the reaction products. Low Cl[sub 2] exposures (<1 L) on Ga-rich GaAs(100) at LN[sub 2] temperature are dissociative, but the reaction saturates at a Cl[sub 2] exposure of about 1 L, and at higher doses the Cl[sub 2] is physisorbed. The main reaction product in thermal desorption is GaCl, but higher chlorides (GaCl[sub 2] and AsCl[sub 3]) are observed in small amounts. Arsenic is desorbed after the desorption of GaCl. As a consequences, an As-rich surface can be obtained after the removal of the chlorinated layer. In metastable quenching spectroscopy (MQS), the electron emission resulting from the deexcitation of He[sup *] (S,[sup 3]S) and Ne[sup *]([sup 3]P) atoms on the clean GaAs(100) surface has contributions from both resonant ionization followed by Auger neutralization (RIAN) and Auger deexcitation (Penning ionization).

• Research Organization: California Univ., Santa Barbara, CA (United States)
• OSTI ID: 5650201
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical &amp; Physicochemical Properties
ARSENIC COMPOUNDS
ARSENIDES
AUGER EFFECT
CHALCOGENIDES
CHEMICAL REACTIONS
CHLORINATION
DESORPTION
GALLIUM ARSENIDES
GALLIUM COMPOUNDS
HALOGENATION
IONIZATION
MILLER INDICES
NITROGEN COMPOUNDS
NITROGEN OXIDES
OXIDATION
OXIDES
OXYGEN COMPOUNDS
PENNING EFFECT
PNICTIDES
SORPTION
SURFACE PROPERTIES