To the best of my knowledge Germany never employed suicide dogs during WW2 (or at any other time for that matter). Russia did however. They trained dogs strapped with a mine to run under tanks where the mine would detonate. However, the dogs were trained to run under stationary tanks and were found to be very reluctant to approach a moving tank. Consequently many were simply shot running alongside moving tanks. Another problem was that if there were both Russian and German tanks in the area, the dogs tended to favour the familiar Russian tanks to the unfamiliar and different sounding German tanks. The project was one of... limited success.

Germany did however have dogs in many other capacities. As guard dogs, sentry dogs, messengers, spotting dogs etc. The Bahnschutz began using dogs to patrol the German railroads as early as 1923. Almost every KZ would also have an SS K-9 unit attached to it with guard dogs, primarily German shepherds, trained to attack prisoners attempting escape. K-9 units were also employed in many other capacities such as overseeing prisoners, patrols, sentries, etc. in almost every theater in the war. Germany did not however train dogs specifically to attack enemy soldiers as a dog is fairly easy to deal with for a unit of soldiers and relatively intsensive in terms of the training required.

Anecdotal evidence also suggest that Germany may have trained dogs as spotters in much the same way bird dogs are used today. The dog will not attack, bark or growl when it spots something, it will merely stand still, body pointed in the exact direction of whatever it has spotted. According to US testimony, particularly from North America, machine gun crew or snipers would then locate the target and engage it.

Germany had two primary training facilities for K-9 units, at Grünheide outside Berlin and in Frankfurt. Each could accomodate 2000 dogs at once. Initially these facilites were officially training dogs for the Bahnschutz and police but with Hitlers rise to power and lack of response to German violations of the Treaty of Versailles in general the guise was soon dropped and the facilities transfered to the control of Himmler as cheif of the SS and Police.

TL;DR - No Germany never used suicide dogs or attack dogs but they did use dogs in almost every other capacity.