Variation in the electrical properties of 100 V/100 a rated mesh and stripe TDMOSFETs (Trench Double-Diffused MOSFETs) for motor drive applications

• Published in: Journal of the Korean Physical Society Vol. 60; no. 10; pp. 1508 - 1512
• Main Authors: Na, Kyoung-Il, Kah, Dong-Ha, Kim, Sang-Gi, Koo, Jin-Gun, Kim, Jongdae, Yang, Yil-Suk, Lee, Jin-Ho
• Format: Journal Article
• Language: English
• Published: Seoul The Korean Physical Society 01.05.2012; 한국물리학회
• Subjects: Mathematical and Computational Physics; Particle and Nuclear Physics; Physics; Physics and Astronomy; Theoretical; 물리학; TDMOSFET; Power MOSFET; BLDC; Blocking voltage
• ISSN: 0374-4884; 1976-8524
• DOI: 10.3938/jkps.60.1508

The vertical power metal-oxide semiconductor field-effect transistors (MOSFETs) with deep trench structures are the most promising candidates to overcome the trade-off relationship between the ON-resistance (R ON ) and the blocking voltage (BV DS ). Especially, 100 V/100 A rated trench power MOSFETs are used in components of many power systems, such as motors and LED lighting drive ICs, DC-DC converters in electric vehicles, and so on. In this work, we studied variations of the electrical characteristics, such as threshold voltage (V TH ), BV DS , and drain current drivability, with p-well doping concentration via the SILVACO simulator. From simulation results, we found the BV DS and the drain current (I D ) as functions of the p-well doping concentration at an ion implantation energy of 80 keV. With increasing of p-well doping concentration in the guard ring region, both V TH and BV DS slowly increased, but I D decreased, because the boron lateral diffusion during the fabrication process below gate trench region affected the doping concentration of the p-body at the active region. Additionally, 100 V/100 A rated trench double-diffused MOSFETs (TDMOSFETs) with meshes and stripes were successfully developed by using a silicon deep etching process. The variations in the electrical properties, such as V TH , BV DS , and drain current drivability, of the two different kinds of fabricated devices, with cell design and density in TDMOSFETs were also studied. The BV DS and the V TH in the stripe-type TDMOSFET were 110 and 3 V, respectively. However, the V TH of mesh-type device was smaller 0.5 V than that of stripe-type because of corner effect. The BV DS improved about 20 V compared to stripe-type TDMOSFET due to edge termination, and the maximum drain current (I D.MAX ) was improved by about 10% due to an increase in the gate width at the same chip size. These effects were reflected in devices with different cell densities. When the cell density was increased, however, the increase in the drain current density changed due to mobility degradation cause by increase in the temperature of the device during high-power operation.