Horizontal nanosheet fets and methods of manufacturing the same

A method of manufacturing a horizontal nanosheet field effect transistor, the method comprising:

• forming a sacrificial barrier layer;
• forming a first layer of crystalline barrier material on the sacrificial barrier layer;
• forming a channel layer on the first layer of crystalline barrier material;
• forming a second layer of crystalline barrier material on the channel layer;
• forming a sacrificial gate;
• forming a pair of spacers, wherein a portion of the channel layer between the pair of spacers defines a channel region;
• etching to remove portions of the sacrificial barrier layer, the channel layer, and the first and second layers of crystalline barrier material outside of the pair of spacers;
• epitaxially re-growing a source electrode and a drain electrode, the source electrode and the drain electrode each including an extension region underneath one spacer of the pair of spacers;
• etching to remove the sacrificial gate and a remainder of the sacrificial barrier layer;
• etching to remove at least portions of the first and second layers of the crystalline barrier material above and below the channel region such that the first and second layers of the crystalline barrier material at the extension regions of the source and drain electrodes have a first thickness and the first and second layers of the crystalline barrier material at the channel region have a second thickness less than the first thickness;
• and
• depositing a gate electrode between the pair of spacers and above the channel region.

A method of manufacturing a horizontal nanosheet field effect transistor, the method comprising:

• obtaining an initial stack comprising an alternating arrangement of sacrificial crystalline layers and channel layers;
• forming a source electrode and a drain electrode;
• etching the initial stack to form regions for internal spacers;
• epitaxially re-growing at least one layer of crystalline barrier material, the at least one layer of crystalline barrier material having a first thickness at extension regions of the source and drain electrodes and a second thickness less than the first thickness at a channel region;
• and
• depositing the internal spacers.