Browsing by Author "Chou, HH"

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A novel fully self-aligned process for high cell density trench gate power MOSFETs
(2004)
Tsui, BY
;
Gan, TC
;
Wu, MD
;
Chou, HH
;
Wu, ZL
A novel self-aligned process for high cell density trench gate power MOSFETs with only four mask layers was proposed. The specific on-resistance can be as low as 0.21 mOmega-cm(2) with 1.5um cell pitch and 35V breakdown voltage. Because this process shrinks trench space but not trench width, the quasi-saturation phenomenon is lighter. After optimization the thickness of n- drift layer and n+ substrate, specific on-resistance lower than 0.1 mOmega-cm(2) with 0.6um technology could be expected.
Trench gate power MOSFETs with retrograde body profile
(2004)
Tsui, BY
;
Wu, MD
;
Gan, TC
;
Chou, HH
;
Wu, ZL
Low specific on-resistance (R-ds,R-on) and low gate capacitance are essential for trench gate power MOSFETs. In this work, we propose a simple method of retrograde body profile to improve the two parameters simultaneously. The retrograde body MOSFET (RBMOS) is realized by high energy implantation. Because the highest channel concentration locates close to drain side, the depletion width at drain side is suppressed so that the channel length can be shortened greatly without sacrificing punch-through voltage. Low thermal budget and easy trench gate process are additional benefits. Power MOSFET with channel length of 0.4 mum, threshold voltage of 1V, and breakdown voltage of 32V is demonstrated. Comparing with the conventional device, the specific on-resistance and the figure-of-merit can be improved by 38% and 70%, respectively.