US 7,491,992 B2
Image sensor cells
James W. Adkisson, Jericho, Vt. (US); John J. Ellis-Monaghan, Grand Isle, Vt. (US); Mark D. Jaffe, Shelburne, Vt. (US); Richard J. Rassel, Colchester, Vt. (US); and Jeffrey P. Gambino, Westford, Vt. (US)
Assigned to International Business Machines Corporation, Armonk, N.Y. (US)
Filed on Jan. 02, 2007, as Appl. No. 11/619,024.
Application 11/619024 is a division of application No. 10/906510, filed on Feb. 23, 2005, granted, now 7,205,627.
Prior Publication US 2007/0108485 A1, May 17, 2007
Int. Cl. H01L 31/62 (2006.01); H01L 31/113 (2006.01)
U.S. Cl. 257—292  [257/291] 6 Claims
OG exemplary drawing
 
1. A structure fabrication method, comprising the steps of:
providing a semiconductor substrate;
forming a charge collection well in the semiconductor substrate, the charge collection well comprising dopants of a first doping polarity;
forming a surface pinning layer in the charge collection well, the surface pinning layer comprising dopants of a second doping polarity opposite to the first doping polarity;
forming an electrically conductive push electrode being in direct physical contact with the surface pinning layer but not being in direct physical contact with the charge collection well;
forming a transfer transistor on the semiconductor substrate,
wherein the transfer transistor includes (i) a first source/drain region, (ii) a second source/drain region, and (iii) a channel region being disposed between and in direct physical contact with the first and second source/drain regions,
wherein the first and second source/drain regions comprise dopants of the first doping polarity,
wherein the first source/drain region is in direct physical contact with the charge collection well, and
wherein the channel region comprises dopants of the second doping polarity;
exposing the charge collection well to light resulting in free charged particles in the charge collection well; and
applying a first voltage potential and a second voltage potential to the electrically conductive push electrode and the semiconductor substrate, respectively, the first voltage potential being different from the second voltage potential, resulting in an electric force that tends to push the free charged particles away from the push electrode.