Electrochemical etching of n-type silicon based on carrier injection from a back side p-n junction

• A technique for electrochemical etching of n-type silicon in aqueous hydrofluoric acid is presented. This technique differs from photoelectrochemical etching because the holes (positive carriers) needed for the dissolution reaction to occur, are not photogenerated. The principle developed here is to inject these positive carriers using a p-n junction under forward bias formed at the back side of the sample. Drift-diffusion of holes through the wafer thickness allows a chemical dissolution reaction at the interface with the electrolyte. To enable holes diffusing through the wafer the minority carrier lifetime must be sufficiently high making the technique well adapted for high resistivity silicon. However, extension to low resistivity wafers has been achieved. Results show the possibility of forming pore arrays and diverse 3D structures.

Ämnesord

TEKNIK OCH TEKNOLOGIER  -- Elektroteknik och elektronik -- Annan elektroteknik och elektronik (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Electrical Engineering, Electronic Engineering, Information Engineering -- Other Electrical Engineering, Electronic Engineering, Information Engineering (hsv//eng)

Nyckelord

Carrier concentration

Diffusion in solids

Dissolution

Electric conductivity of solids

Electrochemistry

Etching

Hydrofluoric acid

Interfaces (materials)

Positive ions

Substrates

Aqueous hydrofluoric acid

Carrier injection

Electrochemical etching

Photoelectrochemical etching

Radiation imaging detector

Silicon pore arrays

Silicon wafers

Electrophysics

Elektrofysik

Publikations- och innehållstyp

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