High voltage metal oxide device with enhanced well region

Active solid-state devices (e.g. – transistors – solid-state diode – With means to increase breakdown voltage threshold – With electric field controlling semiconductor layer having a...

Reexamination Certificate

Rate now

  [ 0.00 ] – not rated yet Voters 0   Comments 0

Details

Reexamination Certificate

active

06448625

ABSTRACT:

FIELD OF THE INVENTION
The present invention relates to semiconductor MOS devices and more specifically to a high voltage metal oxide device with an enhanced n-well region.
BACKGROUND OF THE INVENTION
When designing high voltage metal oxide (MOS) devices two criteria must be kept in mind. First, the device should have a very high breakdown voltage (V
BD
). Second, the device, when operating, should have as low an on-resistance (RDS
ON
) as possible. One problem is that techniques and structures that tend to maximize V
BD
tend to adversely affect RDS
ON
and vice versa.
To overcome this problem, different designs have been proposed to form devices with acceptable combinations of V
BD
and RDS
ON
. One such family of devices is fabricated according to the reduced surface field (RESURF) principal. These devices utilize an extended drain region (in one embodiment a n-well) to support high off-state voltage (V
BD
). These devices have a maximum number of charges in the drain area of about 1×10
12
cm
−2
before avalanche breakdown occurs. This maximum charge sets up the lowest RDS
ON
possible since RDS
ON
is proportional to the charge in the drain region.
To help alleviate this problem, some devices utilize a top layer of a conductivity type opposite the extended drain region (in one embodiment a p-type layer) inside the drain region. The top layer allows for a drain region having approximately double the charge than previous designs, which decreases the RDS
ON
. The top layer helps to deplete the extended drain when the extended drain is supporting high voltage, thus allowing for high breakdown voltage.
One drawback to this approach is that a high drain concentration under the gate region and adjacent to the channel region can lead to premature breakdown when the device is blocking voltage. Thus, what is needed is a drain region that has a high concentration in most areas but provides for lower concentration under a gate region.


REFERENCES:
patent: 5272098 (1993-12-01), Smayling et al.
patent: 5569937 (1996-10-01), Bhatnagar et al.
patent: 5610432 (1997-03-01), Ludikhuize
patent: 5894156 (1999-04-01), Terashima et al.
patent: 6160290 (2000-12-01), Pendharkar et al.
patent: 6207994 (2001-03-01), Rumennik et al.
patent: 6242787 (2001-06-01), Nakayama et al.

LandOfFree

Say what you really think

Search LandOfFree.com for the USA inventors and patents. Rate them and share your experience with other people.

Rating

High voltage metal oxide device with enhanced well region does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with High voltage metal oxide device with enhanced well region, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and High voltage metal oxide device with enhanced well region will most certainly appreciate the feedback.

Rate now

     

Profile ID: LFUS-PAI-O-2845184

  Search
All data on this website is collected from public sources. Our data reflects the most accurate information available at the time of publication.