Methods and apparatuses for mitigating tin whisker growth on tin and tin-plated surfaces by doping tin with germanium

1. A method for mitigating tin whisker growth on a tin-plated substrate surface comprising the steps of:

preparing a tin and germanium-containing solution consisting of an amount of:

a water solubilized germanium-containing compound consisting of 0.1479 g of GeO 2 in an aqueous sodium hydroxide (NaOH) solution,

a water soluble tin-containing compound consisting of 0.340 g of tin (II) sulfate,

water, and

a complexing agent consisting of 0.3919 g of d,l-tartaric acid;

immersing an anodic electrode into the tin and germanium-containing solution;

immersing a cathodic substrate into the tin and germanium-containing solution, said cathodic substrate comprising a cathodic substrate surface;

connecting the anodic electrode and the cathodic substrate to an electrical power source capable of providing an electrical current;

activating the electrical power source to provide the electrical current to the anodic electrode, the cathodic substrate and the tin and germanium-containing solution; and

co-depositing for 8 minutes, using a voltage of 0.995 volts, a current of 14 milliamps, and the tin and germanium-containing solution at a temperature of 18° C., an amount of germanium and an amount of tin onto the cathodic substrate surface to form a germanium-doped tin plated film having a thickness of from about 1 to about 10 microns;

wherein the amount of co-deposited germanium in the germanium-doped tin plated film on the cathodic substrate surface is from about 0.5 to about 5% by weight germanium; and

wherein tin whisker growth on the germanium-doped tin plated film on the cathodic substrate surface is mitigated.

2. The method of claim 1 , wherein preparing the tin and germanium-containing solution comprises adding the water soluable tin-containing compound consisting of the tin (II) sulfate to the water solubilized germanium-containing compound in the aqueous sodium hydroxide (NaOH) solution to form the tin and germanium-containing solution.

3. The method of claim 1 , further comprising the step of: adding an amount of a surfactant/leveling agent to the tin and germanium-containing solution.