Lionel Paul Adda of Allentown, PA, passed away on February 8, 2021 at 99 years old. He was a resident of Luther Crest Senior Living.

Born January 17, 1922 in Allentown to Asturio Adda and Antoinette Casarotto, Lionel fought in WWII as part of the 99th Infantry Division, participating in the Battle of the Bulge. After returning home from Germany, he attended Lehigh University, earning a B.S. in Engineering Physics and ultimately a Ph.D. in Physics.

His career involved three years with the Federal Telecommunications Laboratories, Nutley, NJ, then 33 years with Bell Laboratories, Allentown, where he held the position of Distinguished Member of Technical Staff.

Lionel's entire career focused on the field of semiconductors, including research in the properties of geranium, silicon and gallium arsenide, as well as development in their purification and single crystal growth. He also worked on the development of transistors and integrated circuit devices. He was a lifetime member of the Electrochemical Society.

Lionel hiked and climbed in the Alps of Europe and peaks of Colorado.  He visited many of the National Parks in the West.  He was a hiking leader of the Appalachian Mountain Club, leading many hikes on the Appalachian Trail, and he led a Presidential Range Walk in New Hampshire.  In his retirement, he visited many countries around the world.

For many years, Lionel held the volunteer position of Treasurer and Membership Secretary of the Lehigh Valley Chapter of the Battle of the Bulge Association.

He was a parishioner of Saint Thomas More Church of Allentown.

He is survived by cousins Joan Burton, Carol Passaro and Vanessa and Rhonda Reed.

Friends and family are invited to attend his graveside service at Our Lady of Mount Carmel Cemetery on Mundy Lane in Whitehall on Wednesday, July 28, at 11:00am.

In lieu of flowers donations in his name may be made to the Physics Department of Lehigh University or to a charity of one's choice.