Disclosed herein are methods for forming MOSFETs. In some embodiments, a method may include providing a device structure including a plurality of trenches, and forming a mask over the device structure including within each of the plurality of trenches and over a top surface of the device structure. The method may further include removing the mask from within the trenches, wherein the mask remains along the top surface of the device structure, and implanting the device structure to form a treated layer along a bottom of the trenches. In some embodiments, the method may further include forming a gate oxide layer along a sidewall of each of the trenches and along the bottom of the trenches, wherein a thickness of the oxide along the bottom of the trenches is greater than a thickness of the oxide along the sidewall of each of the trenches.

An integrated circuit device includes: a substrate including active regions; a device isolation film defining the active regions; a word line arranged over the active regions and the device isolation film and extending in a first horizontal direction; and a gate dielectric film arranged between the substrate and the word line and between the device isolation film and the word line, in which, in a second horizontal direction orthogonal to the first horizontal direction, a width of a second portion of the word line over the device isolation film is greater than a width of a first portion of the word line over the active regions. To manufacture the integrated circuit device, an impurity region is formed in the substrate and the device isolation film by implanting dopant ions into the substrate and the device isolation film, and a thickness of a portion of the impurity region is reduced.

A method of forming a metal oxide semiconductor field effect transistor with improved gate-induced drain leakage performance, the method including providing a semiconductor substrate having a gate trench formed therein, performing an ion implantation process on upper portions of sidewalls of the gate trench to make the upper portions more susceptible to oxidation relative to non-implanted lower portions of the sidewalls, and performing an oxidation process on surfaces of the substrate, wherein the implanted upper portions of the sidewalls develop a thicker layer of oxidation relative to the non-implanted lower portions of the sidewalls.

A method of forming a metal oxide semiconductor field effect transistor with improved gate-induced drain leakage performance, the method including providing a semiconductor substrate having a gate trench formed therein, performing an ion implantation process on upper portions of sidewalls of the gate trench to make the upper portions more susceptible to oxidation relative to non-implanted lower portions of the sidewalls, and performing an oxidation process on surfaces of the substrate, wherein the implanted upper portions of the sidewalls develop a thicker layer of oxidation relative to the non-implanted lower portions of the sidewalls.

A semiconductor structure includes a substrate, a buried oxide layer formed in the substrate and near a surface of the substrate, a gate dielectric layer formed on the substrate and covering the buried oxide layer, a gate structure formed on the gate dielectric layer and overlapping the buried oxide layer, and a source region and a drain region formed in the substrate and at two sides of the gate structure.

A semiconductor structure includes a substrate, a buried oxide layer formed in the substrate and near a surface of the substrate, a gate dielectric layer formed on the substrate and covering the buried oxide layer, a gate structure formed on the gate dielectric layer and overlapping the buried oxide layer, and a source region and a drain region formed in the substrate and at two sides of the gate structure.

A high voltage semiconductor device includes a semiconductor substrate, an isolation structure, a gate oxide layer, and a gate structure. The semiconductor substrate includes a channel region, and at least a part of the isolation structure is disposed in the semiconductor substrate and surrounds the channel region. The gate oxide layer is disposed on the semiconductor substrate, and the gate oxide layer includes a first portion and a second portion. The second portion is disposed at two opposite sides of the first portion in a horizontal direction, and a thickness of the first portion is greater than a thickness of the second portion. The gate structure is disposed on the gate oxide layer and the isolation structure.

An integrated circuit including a trench in the substrate with a high quality trench oxide grown on the sidewalls and the bottom of the trench where the ratio of the thickness of the high quality trench oxide formed on the sidewalls to the thickness formed on the bottom is less than 1.2. An integrated circuit including a trench with high quality oxide is formed by first growing a sacrificial oxide in dilute oxygen at a temperature in the range of 1050° C. to 1250° C., stripping the sacrificial oxide, growing high quality oxide in dilute oxygen plus trans 1,2 dichloroethylene at a temperature in the range of 1050° C. to 1250° C., and annealing the high quality oxide in an inert ambient at a temperature in the range of 1050° C. to 1250° C.

The present disclosure provides a transistor, a transistor forming method thereof, and a semiconductor device. The transistor forming method comprises providing a substrate, the substrate comprising a first region for forming a source region and a second region for forming a drain region; forming a gate groove in the substrate to separate the first region and the second region, a part of the substrate along the bottom of the gate groove being used for constituting an embedded channel region of a transistor; forming a gate dielectric layer on the gate groove of the substrate to cover the embedded channel region and to extend to cover a side of the first region and a side of the second region in the gate groove; and forming a gate conductive layer on the gate dielectric layer of the substrate and in the gate groove.

A high voltage semiconductor device includes a semiconductor substrate, an isolation structure, a gate oxide layer, and a gate structure. The semiconductor substrate includes a channel region, and at least a part of the isolation structure is disposed in the semiconductor substrate and surrounds the channel region. The gate oxide layer is disposed on the semiconductor substrate, and the gate oxide layer includes a first portion and a second portion. The second portion is disposed at two opposite sides of the first portion in a horizontal direction, and a thickness of the first portion is greater than a thickness of the second portion. The gate structure is disposed on the gate oxide layer and the isolation structure.