Determining what scientists believe is difficult because, well, this is difficult to find out. One first needs to determine who is a scientist, to what degree, in what fields, in which countries, in what times. In reality, scientists are no more qualified to pass judgement on the existence of GOD than football players. The fact that someone is a scientist, and even brilliant and talented, does not give that person any special access to knowledge about the existence of GOD, perhaps even the contrary.
First of all, it is important to remember that the natural sciences do not pretend to study all reality in all its dimensions, but as their name implies their purpose is to study nature. Physics and chemistry study matter; biology studies the animal world; botany studies the plant world. Those sciences have no relevance about what is outside their field of study. A physicist who studies the density of molecules in a particular metal vessel is not interested in the question of who designed the vessel and for what purpose. A biologist can study the genes of a particular person without having any idea what that person's name is or what that person’s political views are.
Researchers do not pretend to explain all the facts related to the subject of their research, but only those pertaining to the particular field in which they specialize. Anyone who expects that biologist to provide accurate and comprehensive answers to all the questions related to the person he researched (Is he nice? What does he believe? How many siblings does he have?, etc.) is likely to be greatly disappointed.