Sure, and they can also make loans without it. Loans create an asset (the loan) and a liability (the deposit) for the bank. And those things are also liability and asset for the borrower. They need to have a certain amount of reserves and a solvent bank can always obtain them. What they actually did gave banks reserves without the liabilities, and banks use excess reserves to buy assets like bonds, treasuries, mortgage backed securities, the things they can sell to get reserves without raising their savings rate.