Soviets did improvise a lot of anti-tank weaponry, but that's because they didn't have anything decent in service for pretty much the entirety of the war. Their standard-issue anti-tank rifles were so underpowered, the crews were instructed to shoot at the observation slits, and if those weren't accessible, then at the antenna (to at least disable the radio).

These days, infantry taking on a tank would just use an RPG or an ATGM.