Scigazette Monthly Read February issue of Scigazette magazine | Page 21

Artificially introduced atomic-level sensors enable measurements of the electric field within a working semiconductor device

Semiconductors lie at the heart of many of the electronic devices that govern our daily lives . The proper functioning of semiconductor devices relies on their internally generated electric fields . Being able to measure these fields on the nanoscale is crucial for the development of next-generation electronics , but present techniques have been restricted to measurements of the electric field at a semiconductor ' s surface .
A group of Takayuki Iwasaki , Mutsuko Hatano and
vacancy ( NV ) centers , a type of point defect that arises
colleagues at the Tokyo Institute of Technology , the Japan
when two neighboring carbon atoms are removed from
Science and Technology Agency ( JST ) and Toshiharu
the diamond lattice and one of them is replaced by a
Makino at the National Institute of Advanced Industrial
nitrogen atom .
Science and Technology ( AIST ) has reported a new method for sensing internal electric fields at the interior of operating semiconductor devices .
NV centers can be routinely created in diamond by means of ion implantation . A nearby electric field affects an NV center ' s energy state , which in turn can be probed by a
The technique exploits the response of an artificially
method called optically detected magnetic resonance
introduced single electron spin to variations in its
( ODMR ).
surrounding electric field , and enabled the researchers to study a semiconductor diode subject to bias voltages of up to 150 V .
The researchers first fabricated a diamond p-i-n diode ( an intrinsic diamond layer sandwiched between an electronand a hole-doped layer ) embedded with NV centers . They
Iwasaki and co-workers applied their method to diamond , a
then localized an NV center in the bulk of the i-layer ,
so-called wide-band-gap semiconductor in which the
several hundreds of nanometers away from the interface ,
electric fields can become very strong -- a property
and recorded its ODMR spectrum for increasing bias
important for low-loss electronic applications . Diamond
voltages . From these spectra , values for the electric field
has the advantage that it easily accommodates nitrogen-
could be obtained using theoretical formulas . The
Scigazette | 21 | February , 2017