Carrier-lifetime-controlled selective etching process for semiconductors using photochemical etching

Patent · Wed Jan 01 00:00:00 EST 1992

OSTI ID:868181

Ashby, Carol I. H. ^[1]; Myers, David R ^[2]

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1. Edgewood, NM
2. Albuquerque, NM

The minority carrier lifetime is significantly much shorter in semiconductor materials with very high impurity concentrations than it is in semiconductor materials with lower impurity concentration levels. This phenomenon of reduced minority carrier lifetime in semiconductor materials having high impurity concentration is utilized to advantage for permitting highly selective semiconductor material etching to be achieved using a carrier-driven photochemical etching reaction. Various means may be employed for increasing the local impurity concentration level in specific near-surface regions of a semiconductor prior to subjecting the semiconductor material to a carrier-driven photochemical etching reaction. The regions having the localized increased impurity concentration form a self-aligned mask inhibiting photochemical etching at such localized regions while the adjacent regions not having increased impurity concentrations are selectively photochemically etched. Liquid- or gas-phase etching may be performed.

• Research Organization: AT&T
• DOE Contract Number: AC04-76DP00789
• Assignee: United States of America as represented by United States (Washington, DC)
• Patent Number(s): US 5092957
• OSTI ID: 868181
• Country of Publication: United States
• Language: English

Related Subjects

carrier-lifetime-controlled
selective
etching
process
semiconductors
photochemical
minority
carrier
lifetime
significantly
shorter
semiconductor
materials
impurity
concentrations
concentration
levels
phenomenon
reduced
utilized
advantage
permitting
highly
material
achieved
carrier-driven
reaction
various
means
employed
increasing
local
level
specific
near-surface
regions
prior
subjecting
localized
increased
form
self-aligned
mask
inhibiting
adjacent
selectively
photochemically
etched
liquid-
gas-phase
performed
selective etching
impurity concentration
surface region
etching process
chemical etching
semiconductor materials
semiconductor material
minority carrier
highly selective
localized region
near-surface regions
concentration levels
carrier lifetime
photochemical etching
selectively photochemically
various means
near-surface region
selective etch
chemically etched
surface regions
concentration level
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