Groove Power Transistor Design

Power transistors are widely used in civilian and space equipment with their good current amplification capabilities and the advantages of production simplicity.To increase the operating and breakdown voltage of power transistor and to expand its scope of application is the goal of scientific research institutions and production units. In this thesis,power transistor of breakdown voltage greater than 200V was developed by the design of trench isolation terminal,with a layout area 5 times smaller than that needed in conventional junction terminal techniques.The subject comes from a co-operative research project of national space technology,the goal of which is to develop a high-power transistor of high reliability to meet the demand for power transistor applications.The main work includes the analysis of trench terminal structures,theoretical analysis and design of trenched Darlington power transistor,process and device computer simulations of trenched Darlington transistor,trenched Darlington transistor layout design and process implementation,as well as the measurement and test of sample device.In the thesis,different terminal techniques were analyzed and trench was selected as the terminal of the power transistor.Analysis was performed of the power transistor with trench structure.With the aid of computer simulation,the influence of different trench depth,length as well as the oxide layer thickness was analyzed on the device breakdown voltage.The simulation results reveal that the breakdown voltage is to increase with increase of trench depth;trench width is of minor importance for breakdown voltage;too thick oxide layer will raise the electric field in the layer dramatically and therefore should be avoided.The layout design was carried out and the manufacture processes were determined for the transistor by means of above analyses and simulations.Experimental measurement and test show that:with a stable resistor R₁ of 8 kΩand R₂ of 150Ω,a power transistor of trench structure was successfully developed with a breakdown voltage up to 220V,a gain of 4000,the inverse cut-off current I_CBO and I_CEO less than 1μA.Three consecutive sets of sample devices have passed GJB 33A-97 B group assessment.