This graded base happens automatically with the double diffused planar transistor (so they aren't usually called drift transistors).

The 7090 used germanium alloy-junction transistors and (faster) germanium diffused junction drift transistors.

In the 1950s, he invented the drift transistor and was the first to point out that advantages could be gained in various semiconductor devices by incorporating heterojunctions.

The 7090 used the Standard Modular System (SMS) cards using current-mode logic some using diffused junction drift transistors.

Germanium diffused junction transistors were used by IBM in their Saturated Drift Transistor Resistor Logic (SDTRL), used in the IBM 1620.

The drift-field transistor, also called the drift transistor or graded base transistor, is a type of high-speed bipolar junction transistor having a doping-engineered electric field in the base to reduce the charge carrier base transit time.