Study of thermal degradation of mechanical surface perfection and surface photoluminescence (PL) of GaAs0.6P0.4 samples, some of which received high dose room temperature Zn + or Ar + ion implants and others of which were unimplanted, strongly suggests that PL degradation and thermal etch pit formation have a common origin. Thermal etch pits are believed to nucleate at dislocations reaching the surface and these same dislocations act as sources of vacancy injection into the bulk, resulting in PL degradation. Ion implants rendering the surface amorphous are found to retard formation of thermal etch pits and to retard PL degradation during high temperature anneals. The model presented may explain the unusual dish-shaped p-n junction profiles observed when Zn + is implanted into n-type GaAs0.6P0.4 at room temperature and annealed.* Electrochemical Society Active Member.

Boron-and BF2-implanted p+-n junctions are compared. At 50V reverse bias BFf-implanted diodes, fabricated in <100> silicon and annealed in a wet 02 atmosphere, typically exhibited two orders of magnitude lower leakage than B-implanted diodes on the same wafer. The improved reverse I-V characteristics of the BFf-implanted junctions are related to the BFe implant damage. Excessive leakage current in B-implanted diodes is correlated with oxidationinduced defects using scanning electron microscopy. Argon damage implant experiments indicate that an amorphous surface region caused by the BF2 implant prevents the propagation of defects into the junction region during anneal in a wet oxygen atmosphere.The annealing behavior of BF2 implants into silicon has been studied by Mfiller et al. (1). Prussin (2) has related the leakage currents of n +-p + diodes prepared on B-and BFf-implanted silicon surfaces to oxidationinduced dislocations which he refers to as ternary defects. He has also shown that certain combinations of implant and anneal treatment can minimize ternary defect generation and n+-p + junction leakage. The present work concerns the effects of BF2 implants on the electrical properties of p+-n junctions in silicon when BF2 is substituted for boron to implant the p+ region.This paper presents experimental results relating implant damage, annealing atmosphere, and crystal orientation to junction leakage. We found that the leakage current is substantially reduced when large fluences (i.e., ~ 10~5/cm ~) of BF2 ions are substituted for B ions for implants into <100> n-type silicon annealed in wet oxygen. Sirtl etching was combined with scanning electron microscopy to correlate residual damage and junction leakage. Experimental ProcedureArrays of 1.14 X 10-~ cm 2 circular diodes were fabricated in <100> and <111> oriented, 1-2 ~l-cm, ntype, polished silicon. A 7000A thick thermal oxide was grown and patterned as a mask for the subsequent implants. One-half of each wafer was implanted with 2 • 1015/cm 2 of 50 keV B. The other half was implanted with either 144 keV BF2 or 50 keV B plus a damage implant of F, Ne, or Ar. The damaging species were implanted with energies of 100, 100, and 144 keV, respectively. The wafers were positioned at 7 ~ from the normal to the beam axis to minimize channeling.When all implants were completed the wafers were annealed at 1100~ in dry 02, dry N2, or sequential drywet-dry O2 for 100 min to activate and redistribute the boron. The sequential anneal consisted of 30 min in dry 02, then 60 min in wet O2 followed by 10 min in dry 02, and is referred to herein as a wet oxidation. The diodes were completed using conventional processing. Aluminum contacts were applied within the diode perimeter and sintered at 500~ for 10 min in forming gas. Diode samples were next probed with 80V reverse bias applied (VBD ~ 120V) and the leakage current was measured. Sections of each wafer region were then chemically etched to remove the metal and the oxide. These sections were Sirtl etched for 30 sec and scann...

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Elektronenmikroskopische Untersuchungen der thermisch bedingten Veränderungen der Oberflächenbeschaffen‐ heit von GaAS0,6P0,4 auf GaAs‐Substraten mit und ohne Implantation durch Zn ‐ und Ar′ ‐Ionen in Verbindung mit Untersuchungen an Proben, bei denen mit einem Ar‐Laser (4900 A) Photolumineszenz angeregt wurde, zeigen, daß die durch thermisch bedingten Lochfraß und die durch Photolumineszenz hervorgerufenen Abtragungen einen gemeinsamen Ursprung haben.