Simulation and Fabrication of Low Capacitance Lateral Transient Voltage Suppressor

Abstract

Technology advances has shrunk the size of integrated circuits making portable devices much more available and one of the major class of consumer electronics However these IC’s are more vulnerable to Electrostatic Discharge (ESD) hazard since their reduced dimensions leads to problems such as a more penetrable oxide layer caused by reduced oxide thickness Lower operating voltage also requires stricter protection devices Besides the operating speed of modern devices has increased dramatically These all sum up to the need of a transient voltage suppressor or TVS which is designed to protect the IC’s from ESD and electrical surges with a respond speed that matches the electronics today In this thesis the Silvaco TCAD software is used to simulate the fabrication and electric characteristics of a bi-directional lateral TVS The parameters for the desired characteristics are found through simulation Tannar L-Edit software is then used to design photo mask and tape-out wafers in FAB for engineer pilot run Measurement data of the actual device fabricated is collected and compared with the simulation result The clamping voltage measured is about 7 4V which is close to the simulation result The I/O to I/O capacitance is about 0 52pF while the capacitance between I/O and ground is about 1 073pF These measured values are different from the ones simulated The cause to these differences may be the overly simplified calculation for the equivalent capacitance The packaging material also contributes to the overall capacitance making the actual value larger than the simulated one

Date of Award	2014 Aug 21
Original language	English
Supervisor	Wen-Shi Lee (Supervisor)