High-Voltage Transistor and Method for its Manufacture
Assigneeaustriamicrosystems AG
InventorMartin Knaipp
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Abstract
A high-voltage transistor is provided with a well of a first conductivity type, which is arranged in a substrate (10) of a second conductivity type, with a source (14), a drain (12), and a gate electrode (18) above a channel region (KN, KP) formed between the source and the drain, wherein several staggered and nested wells (11, 13, 15, 17) of the same conductivity type extend from the source (14) or the drain (12) into the substrate (10) and wherein the doping concentration (log c) of the wells essentially decreases and is smoothed from the substrate surface with increasing depth (T) and also laterally. In this way, field-strength increases and also unintentional breakdown are prevented. Furthermore, a production method is specified.
Claims19
A high-voltage transistor with a well of a first conductivity type, which is arranged in a substrate of a second conductivity type, with a source, a drain, and a gate electrode above a channel region formed between the source and drain, in which several staggered, nested wells of the same conductivity type extend to the substrate starting from the source or the drain, wherein the doping concentration of the wells essentially decreases and is smoothed with increasing depth and also laterally.
A method for the common production of a high-voltage transistor and a low-voltage transistor, in which the high-voltage transistor is produced by means of processing steps of a known low-voltage process, wherein, for the high-voltage transistor, staggered wells of the same conductivity type are produced underneath the source or drain region together with wells of a corresponding conductivity type of the low-voltage process.
Dependencies are inferred from the claim text.